Redneck, looking at the types of usage you do, you really don't need a computer that does quantum physics. Web surfing, family bills, etc. Sometimes simpler is better. You already have an external hard drive and back-up system. I'd think I'd go small if I were you.
Chromebook. A couple hundred bucks and will do all the tasks you ask of it. Plus, it's super light and you can throw in the 5th wheel or on the bike when you travel. Replace it as needed - no big deal. Local school district issued them to 5000 kids from 8-18, so you know they're damn near bulletproof. Just food for thought.
