It is good to hear from someone else researching the Hills line. I found an article from the Sheboygan Press that had listed two of Richard's brother's name's as Joshua and Daniel and that they moved from New York to Sheboygan County, WI. It also had listed Lyman and another Dan. I did search from the two you mentioned and notice that they lived in the Greenbush area as well. Not many Hills lived in that area that I am aware of. So these could be two of the brothers.The very same article said that Richard was born in Chemung County, NY. That could also be where Joshua and Daniel were born as well.
I've found Richard and family buried in the Greenbush Cemetery in Greenbush, Sheboygan, WI; however, I didn't realize he had brothers that also came. So I didn't look when I went to find them. Next time I'm home I'll stop there and see if I can find them as well.
You can check out what I have on Richard's family on my Cary family tree here on ancestry. Just go to my profile and you should find it. You can share your information by emailing me at firstname.lastname@example.org