Just bought a 99 Pathfinder LE 4WD w/163k. What next?

[PathyMD]

Just bought my first pathfinder today! Happened across this fairly well maintained 1999 R50 3.3L VG Pathfinder with 4x4 for $1500. Drove it about 150 miles today after purchasing it and it runs pretty great for a 25 year old car, tested the 4hi/lo in a parking lot and it didn't have any issues. Only a few negatives; A/C doesn't work, had OBD2 codes of P0115 and P0300, and one small rust spot on a rear door panel (but none under the body or frame!). Got it for a fun recreational vehicle/into to learning to work on cars, not a daily driver. I've done basic work on my daily (oil/fluid changes, A/C blower motor, spark plugs, etc) but nothing very complicated. I want to learn and can follow pretty much any video though. Any recommendations on what to look at (replace/repair etc.) first to ensure that I can make it last as long as possible under my care?

 

Pic of vehicle: https://imgur.com/a/u9PnR6U

[Slartibartfast]

 

The VG33 is pretty reliable. Timing belt should be done if you don't know when it was done last. There's a writeup here, and you can get the service manual from Nicoclub, which will also explain how to chase that P0115 code. P0300, might need a general tuneup. Maybe clean the MAF and throttle body while you're in there. Standard fluids/filters. I don't see rust in the picture, but I'd have a poke around the front strut towers to be sure that they're solid.