just carry enough water and enough sugary foods to keep you going. 50 miles after a month of riding is going to be tough. It took me nearly 3 months to do my first 50-miler...and it left me a bit winded to say the least.

As far as bike stuff, good quality slicks, gatorskins get good words here. Get a solid seatpost, even a ritchey alloy will do better over distance than a suspension post will.

seat...I got by fine on a serfas RX, basically jsut make sure it doesnt put pressure on the soft sposts down below if you know what I mean...otherwise you could get numbness and other bad things.

Pedals...something with good smooth bearings will suffice. Stay away from VP, I've had two pairs, and one the bearings weren't smooth enough to my liking, and the other is heck to lock into (i use clipless pedals).

You might want to look at grips, but only if you are having troubles with teh current ones. Since you sue revoshioft you need short grips if you do choose to mess with them.

Oh, and get some water bottle cages if you dont already

That's a far nicer bike than the one I used for my first 50-miler. and I switched out all of the above. The pedals i used was the Wellgo "lightweight alloy" pedals, about $25/pr. they have some pretty smooth bearings in them, and have nice grip, and are toe clip compatible, if toe clips are your thing.