I think it will be easier for others to try to help advise (though still a hard decision!) with more info, rest of vehicle condition: body- do you live where cars/trucks rust out (not sure where Wentzville is), condition of tranny, any other gremlins that haven't been fixed yet- electrical?
If all else is ok, I would weigh the new cam vs. rebuilt with cost and warranty. Also factor in how much a replacement truck would run minus what you could sell the current beast for in that condition.
If everything else is a-ok, I think I would go for the rebuilt motor w/ a warranty vs used/ probably no warranty.
Good luck!