If you have your policies with high net worth type insurers, e.g. Chubb, Pure, they can write riders that will cover your while gear is in transit. I did this when I moved from NY to Texas because the mover’s insurance is based on gross weight of load and is largely worthless. I wound up keeping most of the riders in place, but there is no reason I can think of why you can’t discontinue the coverage. Usually, such companies want all your business- home, autos, valuables + umbrella coverage. I found this years ago when I bought my first exotic car- the normal insurance companies wanted a fortune to cover the vehicle. I got to Chubb and it was a fraction of that and I shifted all my coverage to them. Unfortunately, Chubb’s rates are quite high, I think in part due to the wildfires in California. We now use Pure, which is a similar type of insurance. But this means changing insurers. I doubt they will write a policy as a one-off if you aren’t a client.
PS: I'm not in the insurance business and somebody who is can probably answer your question more fully including whether any companies will write limited term insurance without being a regular client.
Good luck,