My advice is dependent, of course, on your bike size and type of Civic.

If it's a hatchback, I wonder if it's smaller than an Impreza hatchback? The reason I ask, is that I can get my 54cm (i.e. "medium") road bike inside my Impreza with both wheels on. Front wheel off, I bet that almost any size bike would fit inside.

If it's a sedan (oops, just saw that it is a sedan.... will leave the above in anyway), if the rear seat folds down you should try getting the bike inside through the trunk with or without the front wheel.

Also, I've fit many a bike in the back seat of small cars with the front wheel off. You might want to cover the seat with a blanket or seat cover if you try that.

Just throwing ideas at you.

I have both a hitch rack and a rooftop rack also. The hitch rack can lock to the receiver (locking pin) and the bike locked to the rack. My roof top rack locks to the crossbars and locks the bike with the same lock (Yakima Fork Lift). My factory crossbars I haven't looked into locking them to the car, but the Yakima crossbars I have lock in place.