Congratulations!
I’m a recent RISD grad, and have worked in medium-sized firms that focus on public work. I could have gone to work at a more conceptual design – focused firm, but have no desire to work 12 hour days and weekends for a low salary. RISD prepared me as well as any MLA program in terms of computer technology, but was a little light on some of the more practical aspects of site engineering. The design and studio culture there is outstanding, you share space and coursework with the architecture program and can take electives in the fine arts. The downside is that it is so prohibitively expensive that the bulk of students attending the MLA program are now coming from outside of the US. If you really are more interested in focusing on ecology and the environment I’d probably say Cornell is more in line with your desires. However, if you are OK with being a little more self-directed in that aspect RISD could be good, too. Go for a visit. Ithaca and Providence are both great places for different reasons.