Moving, going to need to build a garage

I'll make it plenty big don't worry about that! :)

I doubt I will ever do HVAC on it, but probably will do the insulated slab and use a portable heater like I do in the garage when it gets cold.

As far as what I do myself, I will do as much as I am confident doing to keep costs down. From what I've seen, 20-30k to have someone build a garage. That's a lot of money on top of the house being substantially more than what I'm in, so what ever I can do to reduce the total price I will definitely do.