That frame should last for a while IF you got it in good condition. What is the rest of the bike like? Because if someone sold you a bike with loose/trashed bearings, what do you think are the chabces they were tight and functioning when he wasn't trying to sell it? If it is in good condition however, it will be fine. The fork isn't too bad, sure they aren't the best, all they have against them is a little bit of flex, they have reasonable internals. Also if you are worried about your bike cracking or going wrong, it is most likely going to form cracks in the linkage plates or blow a shock. But as long as you don't be a hack it will be good, you actually could go reasonably big on that bike as long as it has a landing zone.
Nice bike, have fun and ride it like you stole it.