sounds like you have a pretty cool house!
As someone who has worked in construction, and painted my own house (70 years old) recently, here's my 2 cents:
--dont flip the boards. just leave them there. sand, prime, paint, relax.
1. Prep work is the biggest hassle, but pays the best results. (Just like running, i guess!)
2. Sand it down with 60/ 80 grit and make sure you have a respirator (3M, $35 or so). Use a good shop vac to clean up. Replace/ clean filter every few minutes. If you have a blower attachment on your shop vac, blow off your house prior to painting. Caulk: look for oil-based. Spend the extra bucks on getting good quality, so you'll keep bugs out, and prevent moisture/ rot.
3. (assuming you know about tarping and masking already)... paint sprayer: go with this one from Harbor Freight:
https://www.harborfreight.com/airless-paint-sprayer-kit-62915.html#tt-reviews
. HF has really stepped up their game in tools in the last 3-5 years! Also, read the comments of success people have had. I bought one, had never used an airless sprayer before, and I love it. My wife and I painted our house together, and it was actually pretty fun. I bought a Graco tip (505 or 513 I think) and Graco extension wand. I also ran a small amount of paint thinner through the machine prior to use. HF now sells paint sprayer tips, so you may want to try those. Take the time to read reviews--there is abundant info for what tip to use, how to thin, how to clean, etc. I printed out a few and had them ready in my garage.
4. Paint: I love Sherwin Williams. I was able to get a contractors discount, and did 2 coats of primer, then 2 top coats. It was about the same price as Behr, but SW is much higher quality.
good luck man!