There is a learning curve to doing your own bodywork and paint(two different things). I did mine two summers ago and got great results. I can give some advice and post a link to my build thread where i have photos and details.
Let me try to answer some of your questions but keep in mind, i am not a professional, this is the first time i did a complete vehicle repaint.
The simplest paint job is a repaint in the same color. Each panel depending on what condition it is in may need different prep. If you have a fender that is straight and the old paint is still well-adhered, no you do not have to remove the old paint. Just use wax and grease remover, sand with the appropriate grit, and shoot over it. You do not have to take the hood, doors, fenders off(i did) but you may want to if it’s easier. You will have decisions to make along the way, like to repair rust or just buy a new fender.
I watched many videos on youtube, some over and over to understand the process. And the biggest help was doing business with an auto body supply store where i bought tools, supplies, paint and got lots of advice. Matching the color will be no problem but you will probably have to decide on quality of paint, whether to go with basecoat/clearcoat or single stage.
You’ll need a decent compressor, paint gun for color and clear and a cheap gun for primer. Have another hood, fender or metal panel for testing out filler or paint. It’s really helpful.
Buy quality fillers and paint and it will be easier to get good results. Quality paint in spray cans($$) are more available now and appropriate where needed. If you don’t have the tools, consider doing the bodywork yourself and having a shop spray it. Sometimes classes are available at local tech schools and you get to use their tools and paintbooth, and the guidance of an instructor.
I put a “wow!” Level paint job on my truck myself painting in my yard and garage but buying all the tools and supplies, it still cost me over $2500. Paint is not cheap.
Melrose 4runner 1986 restomod summer beach truck - YotaTech Forums