Newbie here needs advice on recent purchase

Well, just costs a little time to get it running and find out for sure there were issues. As noted the heads usually go first, then the lifters can get stuck if it sat for a while, rings and bearings last to go unless it's been badly abused (run hot, low on oil, etc.). Since you plan on keeping it you won't regret rebuilding the engine as long as you really like the Waggie.

Get it running good on the carb, and if you really love the thing and intend to drive a lot consider an EFI conversion. Won't help a lot in gas mileage, don't expect more than 12-13 mpg average with the carb (10 or so in town and 14-15 on the highway), might pick up 1-2 mpg on average with a throttle body EFI (something like https://www.summitracing.com/parts/sum-240505/overview/). It's not real hard to adapt a late 80s/early 90s GM throttle body from a 350. It's about the right size and tune, and can be half the price of a bolt-on self-learning job... a bit or research and elbow grease (got more time than money?). Then there is the Microsquirt, which requires a good bit of searching for parts. Just under $400 for the wiring and ECU, but you have to source injectors, intake, sensors and throttle body. Easy to end up with $750 in all, but then it's much easier to program for any odd situations/changes. It can be used to run a throttle body injection system or multi point.  Since it only has two injector drivers it's a batch fire controller, not sequential. According to the maker, sequential doesn't add power unless you can tune each individual cylinder (the MS can't, only really sophisticated systems can), and then only 2-3% total power. Sequential does help emissions at low speed, which is why OEMs spend the money to do it. There cost is spread over 100s or thousands of vehicles, so no big deal...

Honestly, the EFI conversion will make it much easier to drive -- quicker starts, not a lot of waiting for it to warm up in cold weather, etc. Will also stay in tune without having to do tune-ups once or twice a year (twice is ideal -- one for summer driving, one for winter...), and will make things last longer because the fuel mixture is closer to ideal most of the time. It's unburned fuel and carbon from slightly rich mixtures that dirty up oil and clog rings...  that's why manufactures recommend 5000-7500 miles between oil changes instead of 3000 now.  It's better to run a little rich than a little lean, so carbs are usually calibrated to do just that. The only gas mileage and power increase between a very well tuned carb and EFI is due to the fact that the EFI system stays in tune with changes in altitude and weather. Carbs tuned for high altitudes don't run well close to sea level and vice-versa. EFI just changes the tune on the fly, so a modern EFI vehicle should run as well at sea level as at 5000 feet above. Depending on how much you drive, the EFI just might not be worth the cost and effort.