I'd say wing it, however you should be able to adapt the generic fantasy adventure in 10th Anniversary, as well as the Ice Princess adventure in the Files section easily. Fudge factor has several as well, which should be easy to change to a solo adventure.

One clarification point. I'm assuming you mean solo as in one player and one GM. If you only want one player, I don't know of any Fudge material. However, there is a series of books by the name of Quest, the first of which is Quest: The War Torn Kingdoms. They are good, and available online, with some people trying to sell them as antiques for about 200-400 dollars, and others who don't realize their value now that they are out of print and selling them for 1 to 3 dollars.

OP: If you do mean solo (just you on your own) adventures, I can recommend the Tunnels & Trolls solo adventures if that's your sort of genre?

Thank guys.  I will probably adapt the one in the 10th anniversary book or "The House" off of fudge factor.  The House seems to be pretty close to a "Alone in the Dark" type setting that will keep my friends pretty enthralled.