I went to undergrad at Clark so I can say a little bit. Basically, I didn't really like Worcester that much, but you get what you pay for; it's much cheaper (bars, groceries, rent, etc.) than other big cities like Boston (obviously). I lived comfortably in a 2 bedroom apt. about 0.3 mile away from campus (6 minute walk) paying about ~$450 a month for rent + utilities, and there are probably even better deals than this because this apartment was kind of a last minute thing. There are buses for public transportation but I never used it once and honestly don't know anyone who did. There is no subway or anything. Having a car or knowing someone who does will be a HUGE help, but not completely necessary because Clark does have an escort service that can drive/pick you up within ~0.5 mile of the campus, which does include a grocery store called Price Chopper. And there are plenty of bars within walking distance of Clark on Main St. and Park Ave.
For me, the biggest negative about Clark was the area. Not all of Worcester is bad, but Clark is definitely in a crummy area. It's a shame because even just 2.5 miles away at WPI is a much nicer/"cleaner" area. There are also nicer bars on both Main St. (near WPI) and Water St., but those are ~2 miles away so it's not walkable (this is where having a car helps). At night, I was never really scared walking around (I'm a guy), but you will learn to avoid certain streets (Beaver St., Crystal St.) and get emails from campus police every now and then about incidents. The campus itself is also pretty small - 95% of it is basically on just a couple blocks (see this map) and with only ~3200 total students, you will get used to seeing the same people over and over.
Feel free to ask any more questions if you have any and I'll try to answer them.