Here's something to think about.
My buddy and I have started playing AD&D again in the Forgotten Realms. He is running an entire adventuring party which he used to run a few years ago until they were tragically and mysteriously lost. (Not in the game mind you, the actual character sheets, his notebooks and all his dice just simply disappeared!)
So we re-rolled everybody and started fresh with everybody at first level.
Growing up playing AD&D in our small community, we typically had to run more than one character at a time and many times, since there was only one DM and one player, we would run an entire adventuring party.
Most of my friends are pretty good about role playing the different personalities of their characters and so forth, but essentially, it's pretty tough to do that consistently since all the characters are created from the mind of a single person.
This adds an additional problem which I recently pointed out to my friend during his last foray into the Haunted Halls. (Using Greenwood's stuff but having been fleshed out, with an upper and lower level by your's truly.)
I could see him making the same mistakes over & over because he only had his perspective of things to rely upon. Yes, he's playing 6 different characters at once, but they all SEE things the way HE sees them.
This is really working against him and I have to say, I don't think it ever dawned on me all these years just how bad this could be for a player and his characters.
It's also frustrating for me as the Dungeonmaster.
Ideally, AD&D and other RPGs are designed to be played with a group of people, one of them acting as the DM, referee or gamemaster and everyone else running a single character. I'm not telling you anything new here but I'm just making sure everyone knows that I fully understand the concept.
But living in BFE where many of the locals rarely even read a book without pictures and AD&D still has that lingering reputation for being an indoctrination into a suicidal, satanic cult, it's VERY tough to find mature players. You might get lucky and fing some fringe or a dabbler or two, but nobody that wants to play seriously or with any amount of dedication. Ones that you do manage to find have never heard of AD&D as we know it and they only want to play this pitiful shadow of the game that exists today.
If you manage to find enough people to play AD&D the way it was meant to be played with a diverse group of people with varying opinions and perceptions, then you are very fortunate. You run into problems keeping the momentum going and it's much easier to synchronzie schedules when the group is only two or three people that live within 10 minutes of each other.
In the case with my one buddy, we are able to play almost weekly and that way, keep the game flowing without significant gaps in playing time.
One thing for sure, despite all the limitations and frustrations that come with running a single player in a dungeon, I am having a pretty good time.
(I think my player might be too.)
And that's the most important part.