K5 Blazer Cheyenne 4wd 305ci 3 speed, starts and drives

1978 Chevrolet Blazer Cheyenne

The positives:1. Original survivor from PA that is in mostly stock condition. I acquired it from the previous owner in PA in 2014 who told me he was the 2nd owner. I had the suspension, brakes, exhaust repaired and added Kumho mud tires. Power steering makes noise but works. Wipers work but intermittent feature does not. Exterior lights work as they should: headlights, blinkers, running lights, brake lights. Dome light does not work. 2. It has 4wd with locking hubs, 5.0L, 3 speed manual. Interior plaid tan-orange-brown interior is comfy. Starts and runs well. I love driving it around on nice days 3-4 times a year, reminds me of riding around in my grandfather's Chevy. It does leak some oil, about 1/2 quart every few months. I start it 3-4 times a week and I leave it on a trickle charger.3. two sets of round and square GM keys.4. in 2014 I added a tow hitch.The problems:1. Has typical significant body rust on both rear quarters, lower doors, door sills, floor boards and driver A pillar.2. No AC and heater does not work. Speedometer and fuel gauges work somewhat, meaning not accurately. Temp, oil pressure gauges work. Parking brake does not work. AM radio works. It has an FM radio adaptor but it does not work.3. Parts of headliner are sagging.4. Both doors close and lock, however the drivers door must be locked/unlocked with a key b/c the lock post is missing.5. Rear tailgate does not open and window does not work and it sags. The window is being held in place by plastic clips. When you drive, the window starts to move downward. Once I park it,I use both hands to lift it back into place.