I'm wondering, ... from someone who was generally in the same boat, whether or not anything can be used from the 2E content?
JMHO, but setting content is entirely useable (it doesn't usually greatly depend on game mechanics). Magic items should be mostly easy to convert over with minimal effort - you'd want to restrict the '+'s of items to the 1 to 3 range of 5e, but aside from that, most classic D&D items just do something arbitrary described in natural language, whether in 5e or 2e, indeed, some 5e items are copy-pasted from 3e and 2e. Monsters can be converted with a little fiddling with AC, and probably need more damage and hps the higher level we're talking. At low level, I've found running AD&D monsters in 5e with little more conversion than inverting AC workable.
Races probably won't convert too easily, and adapting a class would be a major undertaking, much simpler to just choose the closest 5e sub-class - there are 38 of 'em.

Similarly, you can probably find a Background to approximate a Kit rather than trying to convert a Kit directly to a background.
I'm thinking that I should start my 5E experience as a player to get back into the scheme of things before I delve back into being the DM again. Any thoughts on DM vs Player for someone as rusty as myself?
Really, really, JMHO & YMMV, but 5e requires a fair amount of talent/experience to run, but can be done without a huge amount of prep work, and, with a little hutzpah, without really knowing the specific 5e rules in exhaustive detail. Just make decisive rulings at the table and you're fine. If someone points out the written rule is different, just tell them it's a 'house rule,' or 'that's how I'm running it in this specific circumstance.'
It depends on how much D&D was 'like riding a bicycle' for you. If it all comes flooding back, jump in and run. Likewise if you gather some other old-timers who've been away about as long, and or are running for entirely new players.
Playing and running 5e are very different experiences and I'm not sure the former is necessarily prep for the latter.