We decided to install a second row seat that is removable for a couple extra passengers and still have the space for extra cargo.

We found a driver side 2 passenger seat out of a Ford Transit Van on OfferUp for $100, and the tracks on eBay for $100 with shipping. We didn't have to move anything under the van and is very heavy duty.

Material List:
Driver side 2 passenger seat (Ford Transit)
Tracks for Ford Transit seat
Bolts x 8 -Grade 8 Steel, 1/2"-20 Thread Size, 1-1/2" Long (McMaster Carr is good supplier)
Nuts x 8 -High-Strength Steel Nylon-Insert Locknut, Grade 8, 1/2"
Grade 8 Steel Washer for 1/2" Screw Size
Locktite
Steel plates (Lowes or Home Depot) Great idea from: http://www.outdoor-wanderlust.com/
Spray paint
Silicon
Rubber Spacers

Tools:
Angle Grinder
Drill
Stepped Drill bit
Wrench
Socket wrench