Hey natch, I would not replace anything until something breaks. I am a big dude too (6-2/278 lbs.) and I found that some components on bikes are better at hold our larger sized frames than you think. I am riding stock wheels on a 2008 Mongoose (26") and they hold up at Wissahickon Park in Philly just fine.

For the time being, take it to a LBS and have them give it good cleaning and tune up and then hit the Trails!