It does take a lot out of the day, but if you'd like to see AKL it is worth the trip. The lodge and resort are beautiful!
AK is a huge park, so it can be a LONG walk just to get to the front of the park and buses. I would plan on about 3 hours to get out of AK, bus to AKL, eat, and back to the park. It would be much more convenient to eat on your way in, before you go to the park.
We didn't care for Tusker House at all, but Boma was one of our favorites. Sanaa is great too with safari views in the daytime. However, we don't usually leave the park just to eat, so usually eat quick service at AK. Satu'li and Yak & Yeti are both great options.