As far as getting a host is concerned, well, anyone can "get" a host, regardless of the action they offer. Whether that host will actually do anything for you is a different question. For years now, the standard method to evaluate you has been your "theo," or theoretical loss for the action you will provide. You then get comped at a rate of 20-40% of that, depending on the casino, phase of the moon, atmospheric pressure, or whether your host got laid last night.
So you can kind of reverse-engineer this. If you're staying/playing at a Stripoff casino, you can pretty much figure that the comp rate will be on the low side: 20%. Thus, take the retail (rack) rate for a room, multiply that number by five, and you'll have the amount you need to piddle away per day to be considered for room comps. So to get a room, a player at the Platinum Pigsty, which charges $3 per night plus a $196 resort fee, would need to have a theoretical loss of about $1000 per day--and at slots, this would be equivalent to $10,000 daily action. Table game players are evaluated differently, with a postulated theo of anywhere from 1% to 5%, and VP players seem to be evaluated at roughly 2% of action, at least until they twig to the fact that you know how to play at a much smaller loss than that. Some casinos, such as the CET empire and Boyd, use the optimal payback of the machines you play as their metric, which means that for every $100,000 of play, you get a comped doughnut (plain, no sprinkles). If you wish to patronize locals' casinos and/or off-Strip locales, you'll experience closer to the 40% end of the comp range, and will need to play/lose much less.
You would think that you could shortcut this by asking your host, "How much action do I need to give you in order to get a room comp?" Well, unfortunately, they're about as non-forthcoming, shy, and coquettish when you ask such a question as a blushing virgin at a Mormon prayer meeting. What you'll get in lieu of an answer is "Look me up when you're ready to check out and I'll see what I can do." This is obviously not very helpful.
So my answer to you would be: get a host, simply by calling in advance of your trip. Talk to them during your stay and ask them to evaluate your play when you're done. You'll probably be treated fairly generously at first. Then, as they learn that you're not a diarrheal fountain of cash, whatever offers you've gotten will dry up. But when the bloom is obviously off the rose, you can simply kiss that casino goodbye and move on to another one. The nature of casino hostship is such that in a couple or three years, after doing the grand tour of casinos, as it were, you can pivot back to your original casino and be treated as fresh meat, with the same initial burst of generosity that you enjoyed before.