I have lived on campus all four years (dorm first year, campus apartments/townhouses for the other 3). The extra security was really important to my parents, since Worcester is pretty dodgy as New England towns and cities go and they live very far away. Most people I know have apartments by their junior or senior year though, as the savings are pretty substantial. I have had a full kitchen and love cooking so haven’t been on a meal plan for the past couple of years, which also helps.
There is abundant housing in the area but if you want a “student” apartment you do kind of have to snag it early (i.e. October as previous posters have said). However, I’d stay away from the landlords that are accustomed to renting to undergraduate students though as they are more likely to charge a little more for kind of a dumpy product, compared to how, say, grad students live in the same area. From what I’ve heard, expect to pay $300-800 a month per person for a shared place depending on the area, number of roommates, condition of the place, etc. International grad students who arrive in July/August also manage to find places quick so the search is not as urgent as some might think.
As for housing placement for on-campus accommodations, it’s been kind of a mess and has changed every year for the past three years, but I’ve managed to find a variety of situations over the course of my time here.