Same here 1995hoo. I have the Mountain Sled Game saved as its own level in the saved games. It took me a while before I realized there's an alternate path you can take to get the idol.
Do you remember how to get out of the Flooded Cave? This is the one you enter by the poisonous plants at the camp. I get to some shafts of sunlight, which seem to lead the way out, but I'm not able to leave from there or find any further route to take.
Thanks.
The Flooded Cave is disorienting. I've gone through it in both directions and I still sometimes wind up getting turned around so that I end up back at the wrong end where I started. Coming from Bittenbinder's Camp, the exit for the Renegade Fort is at a higher "altitude" (I guess "less deep underground" is the more accurate way to put it) than the entrance from Bittenbinder's Camp. Problem is that it's hard to describe where it is because I blunder around every time I go in there until I get it. After you pass the electric eels there is a place where you have to swim up a short way, then continue ahead. Unfortunately the lighting in there seems designed to trick you. Essentially the best I can offer is that you'll hit a wall and have to swim upwards, then go through another opening, then finally you'll find your way out.
Sorry I can't be more helpful than that. You can definitely get through there and it is a great shortcut, but it's disorienting (and if yours is like mine, the up and down controls work in reverse underwater, I guess because "down" is more in the nature of "backwards" in relation to which way Harry is facing).