The answer should be none of it but that doesn't always happen. 
I have stayed in several vacation rentals with kids and a dog and always treat the home with respect and leave it in a pristine condition.
We had a gr...

To start I'll need some help installing VPF/carpets & painting.

I would make the build investor friendly (renter proof) meaning no carpet, MDF, etc and keep things nice but simple.

Will replacing carpet & pad, and all new paint take care of it, or are other measures in order?

I say this because I learned it all the hard way when I recently replaced carpet with LVP, as I've described in this thread and comments. 

I'd rather have cashflow that I create than a lump sum I need to deploy elsewhere.One house recently was in a nicer market so we did paint, carpet, replaced fixtures, and replaced the hot water heater.

Get a pad of paper and document every single event and thought with times, until this mess is over.

I've experienced that if I allow one contractor to be messy, then the whole place becomes a mess.

-Double wide trailer, new appliance but outdated style (aluminum windows, shag carpet, yellow toilet/tubs. etc) 4 bedrooms, 2 bathrooms, attached double car garage.

Should I replace the carpet and remove the swing set before tenants move in?