One Player Roleplaying

I've known for some time that some of the original D&D games involved single player sessions (as well as sessions involving a larger number of players than contemporary RPGs cater for). Typically, though, these involved higher level characters, who had outgrown the 'party model' of adventuring. Wayne Rossi has recently written about this model for high level play in a post called Party versus Retinue. However, sometimes - like when your gaming group involves people trying to finish PhDs, start second(!) PhDs, pursue anti-folk music stardom, or just people trying to manage the mundane demands of adult life - you have one player and would like to not only run a one-shot, but run a (parallel) single player campaign. In my case, with my wife. Aside from starting at a high level (which is perfectly possible), what other options are there? What games/settings are better suited for running a single-player campaign?

This book is on my office shelf. Didn't give me much advice on running single player RPG campaigns...

Old School D&D seems a bad fit. At lower levels it is dependent on the party dynamic, in which each character fills a particular niche, a combination of which are required for successful dungeoneering. The single player would either have to play a number of PCs, or there would need to be a retinue of levelled DMPCs accompanying the PC, neither seem particularly satisfying. Of course, D&D doesn't need to be about dungeoneering, or a version of wilderness exploration that replicates many of the dynamics of the dungeon. It doesn't have to involve adventures built on the model of published modules, featuring multiple PCs. That said, there was the HHQ (Head to Head Quest - a title I don't like as it sounds too adversarial) series of Fighter's/Wizard's/etc. Challenge modules, but these look to be more a model for a single player 'fill-in' adventure than a model for an ongoing campaign. You could take a leaf from the advice in some of AD&D2e's Complete [X's] Handbooks, which contained advice on running campaigns without the traditional spread of party roles (transforming an 'all Fighter' campaign into a 'only one Fighter' campaign shouldn't be too hard). Or, also from the 2e era, the historical reference books contain plenty of advice for running games that do not feature dungeons or dragons. But if that is the sort of thing that you are going to use D&D for, aren't there better systems for that kind of play? 

Specifically those systems with a weaker degree of 'niche protection'. A skill-based system? King Arthur Pendragon obviously springs to mind. Everyone is a knight. A discussion about player character roles in KAP would run something like this; What's your characters' role? He's a knight. And yours? My character is  a knight. And you? Also a knight. More, the source material involves knights spending years questing alone (often, seemingly, without their knightly retinue!). I know that David Larkins has been running the Great Pendragon Campaign with his wife as the only player, but while I pluck the GPC off my shelf every once in a while I find the whole thing just so... intimidating. Call of Cthulhu also features plenty of solo 'adventurers' in its source material - but they don't tend to last long enough to get a 'campaign' going, and without 'party backup' even a brief spell of insanity - a likely outcome for a PC in CoC - might be an adventure/campaign ender. Which fits with the source material, but I'm not into RPGs as fiction emulators (why would I be, I've got fiction for that), but as games. There is always the option of the retinue - an primary investigator and his or her NPC companions/employees. Or contacts - not all of an investigator's 'resources' need be mobile, the action doesn't take place in a dungeon so having expertise distributed about the city (or other setting) is no handicap, and prevents the PC being accompanied everywhere by a largely silent, mostly invisible, and almost will-less party of NPC niche-fillers. But, for proper solo player fun, Unbound Publishing has produced a very nice looking collection of adventures for single investigators. And it is FREE - Monophobia: A Fear of Solitude. 

Single player science fiction gaming tends to face the problem of spaceship crews, in which it is assumed that the 'party' will be a captain and his or her senior officers. But crews can be so large that they are a collection of unnamed, undefined NPCs, so what is the problem if there a few named and defined NPCs under the command of Captain James PC Kirk? In fact, in situations in which command and decision making is so heavily invested in one character, and thus, possibly, in one player, might not space-faring sci-fi be the ideal setting for single player roleplay gaming? On my shelves I have Stars Without Number (which has the 'niche protection' problem of all OSR games), Mongoose Traveller (which has starting characters begin play a bit less than Captain Kirk), and Rogue Trader (in which one player - the Rogue Trader - is essentially Captain Kirk with skullz! all over his or her uniform, in command of a gothic cathedral of a spaceship exploring the stars beyond the Imperium).

But what about something more like 'traditional' fantasy? A skill-based game with less emphasis on combat seems the best fit. A d100 system (OpenQuest, Magic World, RuneQuest) has obvious attractions, particularly those that have systems to create characters with a bit more experience. With more organic character improvement, they provide scope for a solo player to explore the world according to their interests, and be shaped (mechanically) by those experiences. While my tastes, 'crunch' wise, typically tend towards running simpler systems - OpenQuest over RuneQuest, for example - with just a single player / single PC (perhaps with hirelings/henchmen/sidekick) the crunch factor weighs less heavily, and with fewer characters in play I'd be happy (even welcome the chance) to play with slightly more complex mechanics. An opportunity to put the Combat Manoeuvres of Mongoose RQII (or their evolution in RuneQuest 6, if the book ever finds its way into the hands of a UK distributor) into action, without keeping track of a handful of PCs controlled by players struggling with the rules?  

But my eyes keep falling on my big, fat Warhammer Fantasy Roleplay (1e/2e) books. The career system is the signature feature of WFRP, but in my experience it isn't fully exploited in multiple player campaigns. If a PC really is going to become a Mercenary Captain, he or she needs to go out and do that, not investigate the Purple Hand. If they are going to become an Assassin, they need to set themselves up as Murder, Inc. If they want to be a Demogogue, they need to get rabble rousing. And so on... In a multiple player game, these things are either handled 'offstage' (an informal 'Winter Phase'), which reduces the career system to 'levelling up', or the players need to bring the advancement priorities of their PCs into alignment. A single player campaign, on the other hand, allows movement though the career system to be much more organic, a feature of the play itself, as the PC explores the Old World.

All this said, Solo Heroes from Sine Nomine Press - who never seem to put out a bad book - is not only free, but boasts of being a hack to Old School D&D (specifically, Labyrinth Lord) to enable single player gaming. I'll have to put it through its paces at some point, but at a glance the hack fundamentally shifts the balance of risk in D&D, and for this outing I want the game to (mechanically, at least) run the same whether I have one player or five, to allow the integration of extra players without calling for a 'reality shift'.

Anyway... what system would you use? What would you want to use? What experiences of running single player RPGs do you have?

[edited a little, as it read as if 'you' would want to play a single player campaign with my wife!]