Thanks for all the great advice. I ended up ordering 24/38 rings for my new custom crankset, but what is really cool, is that he is making it so I can interchange parts with my road cranks, and use it on either a mountain or road bike. Its essentially a road triple with a long axle BB to accommodate the beefier seat stays on a MTB. On a MTB, I will use just the inner 2 chain rings, and on a road bike I will use just the outer 2 chain rings, when I want compact doubles. But triples are also options on both. I just need to change out bottom brackets depending on what I want to do.

The outer 2 chain rings will be 94 BCD, so they will accommodate road rings in the range of 30-52 (same as my road compact doubles that I have already). The innermost ring will be 74mm BCD so it can accommodate rings in the range of 24-30. So in the future if I change my mind about gearing I will have a lot of flexibility.

I like that even if I don't adapt to serious MTBing, I could still use the new crank on a cyclocross bike if I decide I just want something light that gets me over packed dirt.

Once I have the crank and BB though, I can also start test riding MTBs. One idea I have is to go to one of those trek for women skills clinics, and see if I can find a shop that would work with me to rent bikes (must be willing to install my custom crank), maybe even with a rent to own option in there. Then I can see for myself what kind of bike I might like best, and how if I really just s--k at it, or if I could get better with some training. Its much harder for me since I can't just walk into any bike shop and test ride anything. I have to find bikes with english threaded bottom brackets, FDs on clamps w a good range of adjustability (cuz my rings are also elliptical and offset), and then a shop that is willing to mount my crank for a test ride or rental.

My gut feeling though is that if I can't ever be comfortable riding the bike I have over moderately rocky terrain, I am not going to adapt well to MTBing. My husband had no problem riding my 26er and his 29er over stuff I couldn't do, so that tells me it wasn't the bike. One day we got into some stuff I couldn't handle, so while I walked out, he rode each of our bikes sequentially out. Made it easier than my having to push my bike out!