I am on the fence if I should get rid of my 2003 chevy avalanche truck. I live in Iowa and the rust is giving me a lot of problems. I just had a brake line break, and I replaced it but, all the other brake lines are getting very rusted. After replacing the breaks I went to go bleed the breaks. The bleeder valve was so rusted out that when I try to turn it the valve it just snapped in half. I ordered new calipers for every wheel because I know I'm gonna run into the same problem. 

I wanted to sell the truck due to the crazy inflation of used cars right now, but I'm about to drop 300 bucks into this, and is it even worth it anymore to sell for a truck that's worth 3-4k? 

The tranny and engine have 220k miles on them and the transfer case has about 90k. I have replaced the front wheel bearing on both sides about 3 years ago, and have put on new fuel tank straps due to them rusting out. Done regular maintenance like an oil change every 3k miles, air filter every 10, but I don't think the transmission fluid has been flushed. The truck is paid off and was given to me by my grandpa at 180k miles. 

Do you think it's worth fighting the rust or should I fix it so she runs and stops well and then sell it?

If you do think that I should keep it the next question is should I put in a new front suspension since mine is pretty toasted due to the rust. 

Also can upload pictures and videos if needed!

Thank you for your help!