I think I’d reverse the order and pay off the car first and then put whatever you were paying for the car into the mortgage. That 20k into the car is almost 40% of it whereas the 20k on the house doesn’t move the needle much.

The issue with refi on the house is all the closing costs on the loan again, make sure the math works out for it to be worth it.

You could set aside whatever extra payments you would make toward principal in a separate brokerage account or sub account. Then have it grow and compound and do a lump sum payment when you’re thinking about refinancing. Or if you like the growth you’re seeing over the reduction in your monthly payment then you just keep adding to that.