Sat in 509, row F, seat 5 and 6. It's about as far from the infield as it gets at Progressive Field. I would definitely encourage that you bring binoculars to help see the batter's at home plate a little better. You might also want to bring a radio headset to listen to a broadcast of the game on ESPN radio or something. It will help keep you more in tune with what's going on down on the field.
Although, if you know the lineup pretty well, you may be able to do without the radio. The jumbo tron is huge and we could see it well from our seats in row F.
The steps are also a steep climb, surprise surprise. There is railing to help you reach your seats but it doesn't help much. I've continued to buy similar seats for years only to move down to better seats near either foul pole on the main level. Hasn't failed me yet but for high demand games, you may be required to sit in your actual seats in the 500s. If that turns out to be the case, you will want to sit as close to row A as possible.

The View Boxes (the 400s) sit in front of all of the Upper Reserved seats (the 500s) and offer a much better view of the game. Take my word for it.