Maintence Time

Well it's time to do some maintiance on my 02 Montana, and i am just looking for some pointers to help me along the way. First off i have to change the front wheel bearings the drivers side is stating to hum and i was told to do both sides because the other is not far along. Is there any tricks to this or is it just like a regular wheel bearing change. i know it is the whole hub assembly has to be changed. when i am at it i am also going to do the front rotors because they are warped. is it better to have them turned or just replace them. Also my rear power quarters stoped working, i tried the fuses and the relays but they are all fine, because all the fuses and relays are hooked up to other stuff which works fine. I just bought a small trailer to camp with should i get a transmission cooler to help the tranny out? It is also time for the plugs and wires to be changed it has 120000 kms on it. i have read a couple posts on this and notice that i am gonna have a fairly hard time changing these. Is the belt hard to change? it is starting to show signs of aging now. also my air conditioner stop working for the third summer in a row. the first time one of the front to rear lines had a whole in it but the dealer fixed it because it was part of the deal when we bought it. the next summer it did the same thing so we took it to a mechanic and it was the other front to back line this time replacing the whole line was going to be really expensive to replace but the mechanic said they were going to have someone come and demonstrate this new tool that would just replace a section of line, so we got that done because it was going to be considerably cheaper. now this summer i went ti use it and low and behold no cold air again. So i am asumming it is a deffernt section of line this time and my brother in told me that instead of replacing the whole line just plug off the two rear lines and buy a can of refridgerent and add it to the system. i know that i will lose the rear air but at least this will get me something. Well i know this is alot but any help i could get would be greatly appreciated:)