I feel like I've answered this question before...deja vu.
So you want to "grind" for 1 day a week?
You sound a little new to the game or at least you want to start learning it and visiting this forum is a good start. If you want to start taking poker seriously I would actually recommend depositing some money online, playing as many hands at the micro stakes as possible and practicing some good bankroll management.
You will see many more hands and therefore be put in more decision making situations that you need help analyzing. Having the electronic record of your hand histories also makes analyzing your poker decisions easier when you post in our ring game hand analysis section.
If you already know all this sorry, but maybe someone else can use it.
As for Atlantic City:
Weekends and nights are the best times to play as there are more visitors, gamblers, and drunks making the mistakes for you to capitalize on. You are more likely to be sitting at a table full of decent players at 1pm on a Monday than you are on a Friday night at Midnight. Holiday's are also a great time to go down, such as these few weeks between Christmas and New Years.
Places to play:
I just want to say I have somewhere around 40-50 hours playing live in AC so its not an amazing sample size to judge all of these casinos. This is a very subjective analysis of the play that I saw when I sat down.
Ceasars: This place had the most fish I had seen, it was actually pathetic and made me a little sad that these people had no idea how they were losing money. It may have something to do with it being the first big casino you face when you drive into the center of Atlantic City, but I would definitely consider going there again.
Tropicana: I like it here, the players seem to be better and there are definitely people that play there regularly (not saying they are great players). They have pretty good comps though for you plan on playing a lot on a consistent basis.
Borgata: Nice ta-ta's, decent drink service, younger scene, lots of okay players that think they are the next Gus or Daniel. Kind of annoying.
Showboat: Decent room, but kind of far from the main drag, if your gonna go there, play at the Taj.
Taj: Lots of action, good and bad players everywhere. Money is seriously flying everywhere. Be ready to make decisions for your entire stack.