Welcome to the Forum from NH.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.
I hope that you will become a participating member in the Forum's discussions.
Nice low mileage find.
Regarding sound system recommendations, I suggest that you go to a decent car/truck audio store and listen to different speakers at different price points. When you find a set of speakers that sound great to your liking and fits your budget, then shop around for price. Crutchfield should be in your list of possible suppliers, once you find the speaker (and head units and amps), as their prices are competitive, and they will recommend the proper interface unit for a head unit to preserve any steering wheel controls, etc, if you also purchase a head unit.