When trying to obtain a value on these vans, you'll find that there is no real source for what the van is worth. It will really come down to whether or not the layout is what you want and how much you're willing to pay. Will there be another van that with a lower asking price? Most likely, but when that van comes up for sale is anyones guess. If you want a SMB now and this one fits your budget, is the layout you like, and you want to go camping this weekend, then get it!
I don't think the asking price is that far off. Considering a lot of the 4x4 SMB's of that vintage are still getting mid to high $30's, that would put you right in that pocket if you spent the money on a 4x4 conversion. For example,
http://www.sportsmobileforum.com/for...ad.php?t=15899 this SMB with 4x4 had an asking price of $38k and it is a 2000 with higher miles. It does have the V10 and some other goodies, but thats $16k more than the asking price of the one you're looking at. You could get all those goodies added on for the $16k (except the V10).