I would go K24A2. It might get a little less mpg, but there is no replacement for displacement. Especially because you aren't going turbo. You are already spending the money, you might as well put the best engine you can find in there. Not only that, but you want tall gearing, so the extra torque from the increased displacement will help a lot. Not to mention the A2 was around for a long time, it shouldn't be hard to find one.
[Edit]: something like this would be great.
https://m.ebay.com/itm/04-08-Acura-T...-/323339441653