Building on the earlier suggestion, i really think you should look at your container situation first. If youre in a rush, the type of bin you use matters just as much as how you tie it down. Honestly, be careful with those flimsy clear storage tubs because the lids usually crack the first time a heavy load shifts against them.

• I would suggest getting some Husky 20 Gal. Professional Duty Waterproof Storage Container units. They have a steel latch and a stackable design that makes them way more stable than the cheap ones. Plus they keep dust out which is a huge plus for van life.
• For the actual tie-down, maybe consider a Gladiator Cargo Gear Heavy-Duty Cargo Net. It is way more reliable than just throwing a couple ropes over things because it distributes the tension across the whole load. You can hook it directly to the factory floor points in the ProMaster without any drilling. Just make sure you dont block your side or rear doors with heavy gear. I have seen folks get stuck because their bins shifted and jammed the latch from the inside. Be extra cautious about weight distribution too. Keep the heaviest stuff on the floor and centered over the axles if possible. Safety is the main thing here, especially since you are on a tight deadline. Youll get it sorted tho, just take it one step at a time...

Five days is definitely cutting it close, but i think we can get your ProMaster sorted if you move fast. Honestly, i would suggest staying away from the L-track for now because drilling into the floor this late is just asking for a leak or a hit to the wiring harness. Since you likely have the factory tie-down points, you should focus on mechanical tension systems instead of permanent shelving. Here are a few options i have tested that wont break the bank:

• Erickson 58507 Pro Series 1 inch x 10 foot Ratchet Straps 1200 lbs. These are my go-to for securing heavy bins.

Pros: Massive tension control and high break strength for safety.
Cons: You really have to be careful because the leverage can easily crush cheaper plastic bins if you crank them too hard.

• Keeper 06128 28 inch Bungee Cord with Hook. This is better for lighter gear like bedding or clothes bins.

Pros: Super fast to rearrange at camp.
Cons: These might allow 1-2 inches of shift during hard braking, so dont use them for anything heavy or sharp. I would suggest checking the mounting holes in your van pillars first. You might want to consider adding Dorman 924-419 Cargo Tie Down Hook if you need more points. Just make sure to check the thread pitch before buying. If you get stuck on the bolt specs, let me know and i can look up the torque values for you.

To add to the point above: over the years, i've found tension bars much faster. You'll get it done!

• Heininger 4016 Hitchmate Cargo Stabilizer Bar
• Con-Tact Brand Grip Premium Shelf Liner