I am big with smells. Last season was the first season I REFUSED to use moth balls. it takes WEEKS to get that smell out. I used to go crazy getting out the smell and suggest the below. If this works for moth balls it should help with the New Camper smell
~Fabreeze all couches, beds, curtains, ANY fabric. do this many times over the next week or two. I say use 2 full bottles min.
~Lemon Pledge all wood and fake wood surfaces.
~Bleach all sinks, toilets and shower.
~Use carpet fresh powder on the carpets.
~Lemon or strong scented pine sol or another floor cleaner. Stronger the smell the better.
~Plug Ins at least 2 I say 4 for at least a month. When I am using the camper I will take some out for a while as the smell can get strong. But as soon as I leave they go back in. (If you keep power to the camper)
~Dryer sheets on the intake of the AC unit in the kitchen. Then the smell will go trough all the vents in the camper. You can even let a sheet or two hang out of each vent.
~Last but not least COOK!! Baking cookies or frying something up on the stove might help too.
I know it sounds like a lot but if you do them all I am sure in a few weeks time it will subside at least 85%!
Good luck! Let us know what, if any works the best for you.