Frank3 is right about Ballys, huge bar and they don't seat you. You check in and then go where ever you feel like. The bar is huge, and the curved part overlooks the ocean. The food in there is pretty bad (in my opinion).
Harrahs DL you are seated. However, if you just want the bar, you can go right in and go to left side of the desk and tell them "bar Only". They check you in and then you are on your own to find a seat at the bar or at one of the high tops. You can stand too until a seat is available . Some of the people in line get a little annoyed when you bump them but it is allowed. If one of the hosts are outside the room managing the line, just tell them you want the bar and they send you right to the desk. This is how we do it all the time. Dino and Deb are great bartenders and will take good care of you. You can eat at the bar too. They always have pizza, the soups are usually good, the pasta is pretty good mostly, and the other food is hit or miss.
Caesar's DL is the same as Bally's. You check in and then sit where ever you like. They have a nice bar. We usually sit at the tables by the window, nice view of the ocean. Food is hit or miss. Sometimes they have something decent, mostly I don't care for it.
Of the three I prefer Harrahs bar. Top shelf liquor and they don't use guns. You get served from the bottle.
Enjoy your trip. I wish you luck.