Should I be suspicious of this temp job?

On Monday morning I got an e-mail from a temp agency (via Careerbuilder) asking if I'd be interested in a job in my field at X company in Y town for $24/hour. I've heard from temp agencies before (even got a permanent hire position through one) so I didn't think much of it. I replied that I was and she forwarded my resume to her client.

Later that night she sent me an e-mail saying the client had accepted me for the position and I'd start on Friday or Monday. I thought it was odd that the client didn't want to at least have a phone interview with me. She also attached a bunch of paperwork (employee information, tax forms, direct deposit info) and a form for a drug test at Quest diagnostics.

She called me the next morning to confirm I had gotten all the materials. She told me to fill out the information and fax it back, get the drug test done asap, and she'd go ahead with the criminal check. She gave me the address of the company and said, "You know, I looked it up on Google maps and it's about 15 miles from where you live, about a 20-30 minute drive." (I Googled it later-- it's more like 30 miles and an hour drive.)

I filled out the paperwork, got the drug test done, and even took a trial drive so I'd know where I was going. I arrived at the address but it wasn't X company (a known name) but some sort of pharmaceutical company. There were a few large buildings but I found it odd that a relatively well known company wouldn't have a sign. I also Googled the company name and the address and can't find anything at that location.

She called me a little while ago and said my drug test was fine and asked if I could start tomorrow or Monday. I said I could and she said, "Great, let me call the manager and ask which day would be better for them." She called me back 20 minutes later and said they'd like me to start on the 12th. She apologized for making me get things done so quickly and added that they seemed to want someone to start right away.

I have a bad feeling about this. I've had a few good experiences with temp agencies but I've also had bad ones. I want to believe this won't fall through but I can't help but be cynical.