I recommend that you don't stay on the first floor. Hotel management seems to monitor the first floor more. I have heard of stories of provider being caught and thrown out because they had first floor service.

Get your self one of those vip accounts with the Hilton/Hampton Inn. They are pretty good, free breakfast, washing machines, extra towels if you need them. You can put in a profile of the type of room like with bedsize and floor. They also have online internet reservations. Once you build your points (can get airlines/car rental points also), you get a free room for so many points. Also be sure to have the provider not come to your room to late. In the bigger cites I would go for the Hilton, they have nice big lobbies and have easy access to the elevators.

One of the first things I do when I land in town, is to get the protection equipment, paper towels, and water. You need to drink alot of water if you want to have multiple pops. Also the provider likes nice bottled water.

Sometimes it is nice to see if there is a outback or another nice restaurant nearby that has room service. Sometimes providers like to have a nice steak after having a few rounds.

Always get 2 access keys and make sure that both work with both your room and the side access doors.

I've stayed in (and had provider visits to) or visited providers in any number of medium to large hotels, and never had a problem.  Unless she's seeing you in the dead of night, there's usually enough traffic in a hotel lobby that a provider will go unnoticed.  Now, obviously, if she dresses provocatively, that could create a problem, but most providers don't.  

One strategy that may or may not work, if you can do it, is to meet her in the lobby and escort her up to the room.  She gets the security and consideration of being met by a gentleman; you get the cover of appearing to meet a colleague or friend.

I've had good experiences at Doubletrees, Embassy Suites and Four Points.  I'd imagine Hyatts and Marriotts would be the same.  I'd avoid first-floor with exterior exit.

I would recommend staying in the larger hotels, as there is alot of traffic coming and going.

If a conservative dressed lady walks into a large hotel, she will blend in.

When touring, I Always make sure that I stay in large hotel. The Only Person that notices that I'm there, is my Maid! (of course LOL) I tip her very well and treat her very nicely.
Kindness will get you Everywhere!

If you need help finding a room in Phoenix (my stopping grounds)
Let me know and I will be more than happy to help.

My only input is to avois any hotel where you need a key card to access the elevator.  Several holiday Inns have these types of security measures which will require you to meet the provider in the lobby and bring her up.

My preference is to have her just come up, especially if you're going to see several providers at the same place as I have in the past.