Newbie with a couple of questions

[sc1jeepster]

Hi. My Name Mark, I am from NJ & new to this forum. I have couple of questions about my Chevy's. I am thankful to any and all help. I have a 78' sidestep & a 76' Blazer
The sidestep needs new tires It has 275/60 15's on it now but they don't grip very well in the rain! Question, What other sizes work best for this truck? it is 2wd. 2nd question the 76' blazer needs the trans replaced ( I blew the low gears) What is the best way to remove it ? tranfer case forward or pull the engine then trans? I am only asking because I am going to remove the front end of the Blazer & start a light resto on it in the spring. I was not going to remove the engine because it is in perfect condition but if it is easier,I'll pull it. I do not have a lift & i was thinking i might not be able to get it high enough to pull the trans case from under. Thanks in advance for any and all help