I second the wandering nature. I have a flock of 11 guineas and many many chickens and a few ducks too. The guineas group together more than the chickens and less than the 6 ducks, but the guineas wander, and make noise (which I love). We are new to guineas, and they didn't roam until last fall, so cannot tell you about the ticks, but our chickens did seem to help the tick population the last two years.
We live in the middle of 10 acres and the silly guineas bee line down the lane squawk around the lane and then all come squawking back to check in with the rest of my mixed birds. They are comical. I love them, however, my husband wouldn't be sad if I stuck with chickens instead of guineas, he isn't as enamored with their ways. He thinks they lack intelligence, I think they are very habitual creatures that don't deal with change well.
I have trained them to overnight in an enclosed run. Basically as mentioned earlier, I also kept them in the enclosed run w access to the chicken coop for a few months after off the heat lamp. It is their home now and even if they miss coming in at night, they roost on top of the covered runs mere feet from the rest of the flock. I discourage that due to predator risk. . I have built a covered but open to the enclosed run shelter for them, and they hang out there on windy days, but seem to sit on their perch exposed to the night air, wind, rain, and snow with no Ill effects. They did fine all winter and chose to seek covered shelter maybe 1 or 2 nights out of the winter, but generally preferred their perch in the open within the enclosure. Occasionally a few would roost with the chickens but generally they stick together outside.
I didn't seem to answer an questions, but I like the place they have on our little farm, I can't wait to see how they do this summer since they free range most days now. I find them enjoyable and I am amused by their antics. Sorry to tAlk so much about them, but if you want a flavor of them , I hope I helped!