1) There is a given order of specialties that you rotate in (my class was IM, EM/neuro, FM, surgery, psychiatry, OB, and peds, but I think the order has changed for the current M3s). You rank your preference on which specialty you start with, and then you proceed through your clerkships in the above fixed order (peds -> IM and then you continue sequentially).
2) After you have your fixed order of specialties, you rank your preferred sites per clerkship. There are many sites per clerkship and it can be overwhelming at first, however students from previous years will always compile a yearly spreadsheet of clerkship reviews, giving you a rundown of their experiences per site. It was a helpful and honest resource overall for me and I'd say overall I had a smooth clinical experience (keeping in mind the chaotic nature of clinical rotations in medical school everywhere). Best places to do rotations depends on clerkship and clinical interests. Advocate Lutheran and Advocate Christ are consistently good for most/every rotation.
As mentioned there are a wide variety of rotation sites, some of which are a couple minutes walking distance and others which are farther (think Rockford, Barrington). The farther rotations aren't exactly the most desirable but people make it work. For example, the Rockford rotation for FM and Kenosha rotation for surgery are both lauded for its education opportunities and interactions with clinical staff, but the drives are brutal especially coming from the city. RFU does get periodic SSARP Emergency Grants which helps with resulting finances (can't guarantee this will be here for incoming M1s since it's COVID related) but you do have to apply for them.