Many of us have family we trust to do well with our bunnies, but my gut feeling here is to go with the pet sitters who are experienced with bunny care. I think you can establish a history with them this time, then know they will be available from now on. Family and friends often are not, so it’s sometimes a better set up to pay someone to be responsible – they have a business and reputation to preserve, not to mention bills to pay with the income so they are invested in doing the best job.
Ask them if a pen will work, if it just needs to be covered, or is too large and out of the question. If the latter, ask how much exercise time your bunny will get daily. My vet sits pets in her office, and I believe the cages are simple, but they let each one out for a hop around the office enough to get a workout. Your bunny will not be freaked if they are good handlers and stick to your feed schedule. Also, providing familiar toys or blankies can help a lot. When I had a friend who cared for Spockie, before I met this vet, I tied a used knee sock inside the cage bar so he could smell me. He used to lick it constantly, but he played nicely with my friend’s family and was totally content. He was in a small cage most of the time, with a hop around their kitchen daily.