Kinda goes along with my thought of after filling in the hole sticking a cross in the soil to mark where the stash is. Helps to paint something on the cross like "RIP Fido the Dog". People will think it was a dead pet and move on.
Use a vacuum sealer. Divide up the stash and put some in each bag. Vacuum seal and that will keep moisture out for a long time. Don't put all of into one bag because if something does go wrong then only part of the stash will be damaged. Place the sealed bags into a metal container to prevent damage to the bags by the shovel. Glass containers are too easily broken.
The title of the thread mentions storing for a few days. My idea is to use a large flower pot for each part of the stash. Put some soil in, then the package, then fill up to the rim. Open a pack of flower seeds, scatter and plant them. Put the basic info on tags and markers and everyone will think that you are an active flower gardener. When the few days are done retrieve the stash, refill the pots, add more seeds and everything will look normal.
That method allows someone to keep the stash on the porch, patio, balcony or in the backyard garden. It will not seem out of place.
If the stash has to stay hidden for an extra week or more it should still be OK as long as a decent container is used to hold the vacuum sealed bags.