Welcome to OCC! Congrats on the getting the 100, single family owned machines are special.
I believe a creeper is necessary for use with a thrower or tiller, you don't want to ride the clutch to crawl along. I don't think speeding up the thrower will make any difference in its performance when paired with a tractor with no creeper. Creepers can be bought as can throwers, since you were given the tractor, spending a little money to suit your wants seems reasonable. Personally I think 42" is too much thrower for 10hp, others will disagree. I would look for a 36" thrower (and a creeper). $275 for a lightly used, complete qa42a is reasonable to me. I've seen plenty in poor condition advertised for $250. As far as pushing snow, 10hp is more than enough. Even with weights and chains, you will run out of traction before you stall out. I have made piles as high as my car with my 8hp Original (no creeper).
Bill