New to Munchkin.. have a few questions

[Zanatar]

First off, I want to say how much fun this series is.

I was introduced to it, for the first time this x-mas, as my friend bought Munchkin Zombies. My son and I loved it.

I'm a huge crpg fan, and from the old days AD&D.. so I figured the original Munchkin version would be even more for me. We bought it and as a Family (my wife, Son and Daughter), played it and we all love it.

I don't plan on mixing Munchkin genres just yet (Zombies, super heroes, etc) I'd rather first stick to original Munchkin and work on it's expansions for now.
We will probably start one at a time, with Munchkin 2 and eventually up to Munchkin 8 in time.

I have a few questions:

1) Given how I plan on playing.. would you all, knowing what you know about each expansion.. suggest I get them out of order and not 2 through 8? If so, what order would you suggest, and more importantly why?

2) Once I do start buying the expansions for Munchkin 2 through 8. How exactly do I mix them? Do I literally just throw all the cards together?
Won't that make it so I will no longer know which cards are related to which expansion? How will I know how to separate them back to there own expansion box?

3) I'd also imagine once I have all 8 expansions, I mean doing the math, assuming each expansion is 112 cards.. and the original being 168 cards. that's 952 cards. That's quite hard to keep in two stacks of Door cards and Treasure cards. They would be quite tall. How do you guys do it? Do you have that many cards in both those stacks?

Thanks, Zanatar.