Please describe the perfect incall.  Downtown, suburban, security-locked building, house, parking garage, parking lot, etc.  What worries you most about incall locations?

Large, lots of entrances (exits), parking free or affordable.  
Incall: mirrors and a sex swing.  
Laundry in apt it cheap within the building.  
Xxo,
SG

One could make a good argument for or against any location. I believe what matters most is to act like you have been there before and that you belong. Some providers make give clear directions on what to do and what not to do. For example don't stand around the outside of their location waiting to be let in or buzzed in. Just blend in so not to attract any attention to them or you.

When client arrive at an apartment or hotel room, give them the room number and instruct them to enter without knocking. Neighbors hearing doors being knocked attracts extra attention.

I found the key and let myself in and when I opened the door, she was on the bed masturbating and started begging me to get inside her.  That was one outstanding incall appointment!

Apartments/Condos have secure entries, plenty of free parking, many visitors that don't live there 'buzzing in' and few have cameras and only at entries. Hotels have cameras all over, from parking lots, entries and hallways and keycards and a bored security person can track provider and clients every in/out with time stamped video. Plus easier for LE sting using same info and you don't even know big brother is watching! Some providers rent small efficiency apt. just for business and live somewhere else. Now that's discreet! And in suburb with easy freeway access.

in most cases it would not take long for neighbors to get suspicious.

While I agree with your thoughts on the comings & goings of apt/condo buildings, I do strongly disagree with the 'burbs in general, always and forever. More stay at home people looking out the window...nosey nosey. Some areas are so damn quiet that every move can be noticed by someone.  I really like the whole "act like you belong" or "blend right in" theories. I like to practice those ideas for outcalls, no matter where they are.  

I just dreamt about a sex swing but I'm not full service.  May this is a portend that you're coming over to visit?  

then would be a mid level hotel. no flea bag hotel and no very high end hotels where I wouldn't fit in without a suit or need a room key to use the elevator.

There are a few that this was their undoing and resulted in a lost "Holiday"

If it is a place with a lot of people coming and going and where it is not easy to see the the clients going in and out of her place it can work just fine, particularly if she opens the door for you or leaves it unlocked.