I think what you're asking is:
Do you have guidelines for building a town that feels legit? With the correct number of fleshed out businesses and services?
As in how do you know what’s is the correct number of brothels to establish in a Medieval Vegas? (The correct answer is always 1 more than you think it should be).
Kinda.
I find random generation programs to be,... work.
But then I am Lazy.
The PCs will tell you who they want to see.
Don't work too hard at it. Just have a list of names and occupations/stores. The rest will write itself.
Like anything you can get as elaborate as you want, but will the players really care that you have names, home addresses, hair color, hit points, family afflictions, and baby stories for all the swine herders in a 5 mile radius?
(Well they might be impressed by your level of OCD at that point and ask you to seek professional help- but I digress.)
If you're still Jonesing to give your players the Un-abridged Annual Census and Chamber of Commerce Report, you might try this. It’s a PDF of the AD&D 1st Edition Dungeon Masters Guide
You have the Internet at your finger tips, GO FORTH AND TORRENT!
Here It’s on page 89-92 of this PDF
I personally use the formula of 1 to 100. One person doing a specialized job (merchant, craftsman, doctor, etc.) can service the other 99.
(Example: 1 black smith for every 100 people or less, 10 Doctors to every 1000 Citizens, etc.)
The exception to this is Farmers, Waste disposal and Law enforcement.
In small communities (100 or less) everyone feeds and picks up after themselves and generally behaves.
In bigger cities (+2000) one in ten people in the population has to make food for the others or pick up their garbage or keep them safe.
The more people the rowdier it gets.
Anyway what do you really need besides a butch looking baker and candlestick maker?
Oh, well and the Town Drunk (Oh Farnum, your post traumatic stress is hilarious).
In my opinion players want memorable NPCs,... but sometimes all they want is an ATM. Offer a few memorable ones with personality and treat the rest like ATMs.
If you want to add personality to your NPC's I'd just steal from an already fleshed out town, (see Diablo references above).
I hope that answered your question, If not I hope it entertained
Grugglington IV. (That’s my New goal,… I don’t need any others).
-Cheers!