I also have a van towing my 183 Hybrid... I purchased a Harbor Freight 2 camera one monitor security system. This uses a hard wire, but the system only runs about $70 or $80 if not on sale. I mounted one camera on the back bumper to a block of wood and strapped it on with nylon ties. I ran the wire that it came with which includes video and power under the trailer to the tongue and tied it down. It is long enough so that the wire terminates inside the rear of the van. I then purchased extension wires of the same type and ran it to the front of the dash to the the 5 inch screen it came with.
The camera gives a pretty large field of view to the rear.
The second camera I screwed to the back edge of the van roof and it looks down at my hitch ball. I use it to help line up when hitching. THe screen will auto switch from one camera to the other or you can manually switch. The Screen is powered by an added 12 VDC cigar lighter plug, and that in turn powers the camera through the cable. Everything cost about $100 including the 12 VDC power supply and the added 25 foot extension cable.
Defender Security 25' White CCTV BNC Video/Power Siamese Cable | 82-16605 (8216605) | Defender Security
You will also need an BNC male to RCA male and a BNC male to RCA female adaptor for the extension cable as the HF model only uses RCA plugs on both sides of their cables.
I also wrapped the ends connecting the cameras in large heat shrink tube for rain protection.
No need to worry about wireless connections or if they will work and cheap.
hope this helps