Here is my cart:
1- All guns are covered.
2- It has a cooler.
3- It has a bag to place my gear and ammo in.
4- It has a toolbox for "stuff".
5- It was cheep. It Cost about $90.00.
I got the cart at a thrift shop for $15.00
Right now the bag has:
1-  400 rds of pistol
2- 100 rds birdshot
3- 25rds slugs
4- 400 rds rifle
5- 6 pistol mags.(hicap 140mm)
6- 8 rifle mags (3 30rds, 5 20rds) ar15
7- 3, 32oz gatoraid bottles

The bag come from Home Depot It is a large cooler utility bag and cost $8.00 full retail. It fits perfect between the two guns and on the seat. It has lots of small pockets on the inside and outside that fit my pistol mags great and also large pockets that will hold the rifle mags.

I also got the 2 sided tool holder at home depot for $12.00. It will hold almost everything I would need when your at a stage and you need a tool or a chock tube. Plus lots of other stuff.
The gun bags and the mounts came from Allright Products. www.allrightproducts.com
I used 2 of the Pack rack mounts and 1 RackBag for shotgun and 1 RackBag for rifle.