The Russians' transport was mostly lost during the landings or couldn't disembark from the landing barges; so for the most part the Russians guns were either pulled forward by men, or shuttled forward by what trucks they had.
The same could be said for the Romanians, at battalion and regimental levels, they have mostly horse-drawn A-T Guns with what truck pulled A-T Guns heading further east to stem the landings.
So A-T Gun Section cost 3 TP with the following modifiers:
+1 TP set up on Map
-1 TP set up In Reserve
+0 TP set up off map
This means, yes if set up off map it will have to be manhandled on the map.
With regards to the Gun movement issue: a possible ERRATA to come out in the future will looks something like this:
Russians (RG: G1-4): v- Increase RG cost by 1 TP for a Prime Mover (GAZ-MM) for each gun.
Romanians (RG: G1-4):v- Increase RG cost by 1 TP for a Prime Mover (Wagon) for each gun
Germans (RG: G5): v- Increase RG cost by 1 TP for a Prime Mover (Buessing-N AG 4500) for each gun
Germans (RG: G6-7): v- Increase RG cost by 1 TP for a Prime Mover (Opel Blitz) for each gun
TM 27- PRIME MOVERS: If the extra 1-TP is used to requisition a vehicle (truck/wagon) to pull a gun, this vehicle is designated a Prime Mover. A Prime Mover's primary purpose was to move the gun and to supply it with ammunition. If a Prime Mover is destroyed or captured, its gun is immediately under Ammunition Shortage (A19.131) and cannot have its special ammunition replenished (C5.28), this state will continue for the remainder of the TM [EXC: If another gun is destroyed, then its gun-less vehicle can be reallocated to any vehicle-less gun].
Cheers
George