We don't carry our bikes on the ladder. I think the weight would eventually destroy the ladder from bouncing loads. We do carry them on a hitch-mounted bike rack, but we also tow a Jeep, so we use a double hitch to allow us to do both. The double hitch has one receiver over the top of the other. This is what it looks like:
https://www.amazon.com/CURT-45792-Du...hitch+receiver
You may need an adapter to downsize the top receiver for the bike rack, and maybe an extension on the bottom if you are towing. I also pay attention to anti-rattle hitch pins so that nothing moves around due to loose fit in the receiver.
For bike covers on the bike, I have found that barbecue covers work great. You just have to find the right size. Good luck with your project!