Apartment/condo hunting

Hi, glad to be here!

I've been living in various parts of Thailand for about a year and a half so familiar somewhat. Currently I live in Jomtien, outside Pattaya, and want to make the move to Bangkok, near the BTS. My apartment budget is 12,000 baht monthly, so i'm thinking sukhumvit 80 or so. The On-nut area but not opposed to better suggestions since i have never lived in Bangkok before.

I am retired so location of work is not an issue but the area I live must be close to the BTS because I have no car.

My question is this: because i now live in pattaya, approx. 2 hours away, dealing with a real estate agent for apartment hunting may maximize my time when i come to Bangkok to look at an apartment. An agent can show me multiple apartments. Rather than coming two hours away to look at 1 or 2 apartments from an ad.

1 Does anybody know of any good agents  who deal in finding apartments in this price range?

2. I am open to suggestions of areas along the BTS lines for apartments in this price range. Qualifications for the area also is safe, quiet, residential and accesible to supermarkets etc.

Thanks for your time.

Aron