It is okay to say no. Be kind about things, but do what you need to do. We told my inlaws to please give us some time to bond and it was the right thing to do. Same with my folks. My in-laws came 5 days after the birth and it was nice to have some backup in terms of holding the baby while we slept for a few hours, etc, but in other ways it still felt a little bit too soon. I appreciated other people loving the baby but still wasn't ready to share him as much as MIL wanted, I had to do battle over not bottle-feeding (so MIL could feed...but I was BFing and not pumping yet, and wasn't about to start earlier than planned just so she could feed) and we also had a few issues where DS was crying and wanted to nurse and MIL would walk him around and try to comfort him and sort of got aggro about giving him back! I think she just got new-baby intoxicated but boy did it piss me off, on top of all of those hormones! I was also was exhausted and just wanted to hunker down with my baby in my room and not have to talk and interact with anyone who required more of me than grunts.
Also, my in-laws stayed at a hotel but didn't rent a car so DH had to pick them up and drive them home every day which was simply ridiculous when we were as tired as we were and he drove them around to get takeout, etc, because they were nervous about the city. (They don't cook). So it was really hard having htem there because not only did they NOT help much, but there WENT my help, taking care of them.
So this time around, we will probably ask them to wait just a bit longer, and insist on them renting a car, and we have food (frozen) and if they get hungry for something else, well, we will send them out to eat.