James,
A few thoughts on modern light cavalry for your story:
Vehicles: dirt bikes, ATVs & 4WD pickups. The big problem is noise, bikes & ATVS are very, very loud, so perhaps electric with much better batteries? That gives a mild sci-fi twist. The trucks could be for supply, medical, field kitchens, larger weapons.
Weapons: current infantry weapons up to mortars would be adequate, but anything man portable would work. Laser designators for air or artillery strikes.
Air cover: small drones for recon & attack.
That's all that's occurred to me.
Don Quotays
Sir, I have, as a pedestrian, long been fascinated by the possibility of petrol-nomadic life for those who exodus the urban-suburban continuum. The movie Road Warrior is still a fair example of what will eventually come for some.
In my novelettes Ghost Snatcher and American Dream Boat I do make the case for this contingency as both an offensive and defensive lifeway.
I think the horse-powered nomads of the past, particularly the earliest ArŅans with their carts and chariots and American settlers of the West with their horse-riding scouts and guides and the lumbering wagons drawn by beasts, serve as an example that multiple types of transport, with various speeds and fuel requirements will be needed to form a survival caravan.
When I was on Soapstone Mountain with Bob and his son in 2019, I noted that this had already taken form amongst suburban debt slaves seeking mountain sanctuaries for a long weekend
The typical family caravan consisted of a pickup truck, hauling a camper and a flat-bed which hauled ATVs. For a real survival caravan I think that high mileage and light dirt bikes make the most sense for outriding in mixed road and terrain conditions over the long distance and that ATVs be reserved mostly for long range perimeter scouting and foraging once a camp has been established.
The biggest consideration is fuel.
The Deep State and the rising Info-Medical-Security-MC Corporation Complex will do what they can to reserve fuel access for their minions and deny it to their avowed enemies—the American paleface. For this reason, I think that the lowest fuel consumption light vehicle is crucial, and in particular a light vehicle with two occupants, so one person could ride shotgun, for road travel. Operationally, a lot of uncommitted movement and scouting and probing with such light motorcycles, with a two-man light vehicle as a communication hub and firebase would be desirable.