The Internet tells me that specific unit weights 137 lbs. Mine (a Champion) has a pair of wheels and a folding handle on it that makes it relatively easy to move around on flat surfaces. It's not as easy to move on steps.

Any generator that outputs 120VAC (in the USA at least) can be safely and legally used with a properly installed transfer switch.

My generator doesn't have any semiconductors in it and I expect that it would start and run after an EMP. I imagine the Generac model you mention is similar. I don't begin to have enough fuel on hand for that to matter to me, for more than a few days using the generator sparingly.

My generator has a long-term storage procedure and starts within 2-3 pulls after a year of storage if I follow the procedure correctly. If you don't follow the manufacturers' long-term storage procedure and the manual doesn't suggest an interval to run it periodically, I'd guess at running it for an hour a month.

Oil, gas, air filter, rare spark plug changes (I have a couple spares), and mine allegedly needs a new fuel hose every five years. I've always done that pre-emptively, never having had a fuel hose failure.

If there's a model you're particularly interested in, I bet you could download the manual for it before making a purchase.