New to me, can't wait

[Shammua]

Howdy all,
I have a 2000 GZ in my garage that I am about to purchase from a friend of mine after I got it running. They can't afford to replace the dry rotted tires or anything else such as insurance and what not.... Anyway this is my first bike and I liked it the first time I saw it then after cruiseing this site a little bit I fell in love with it since I see it can be made into a bobber. I love that style and eventually it will get remade.

I have a few questions for everyone that will greatly help me out.

1. I am having a hard time finding replacement tires, is there other sizes that will work to replace the 111/90-16 and 130/90-15M?
2. I put in a new battery (it isn't run hardly at all) but the battery doesn't seem to hold a charge. Is there anything like an alt. for this? I am knowledgable about cars and trucks but am fairly new to motorcycles.
3. This bike has been sitting for YEARS, (I got it started and replaced plug) what else besides the oil should I check?

More to come and I hope to get to know everyone on here and maybe even make excuses for a road trip or two.

Matt Holland