The Imperial Guard cannot always just walk over to the warzone. The most common option is to have the Imperial Navy smash their way into the system and deliver the sledgehammer that is the Guard in person.
I have a sizeable BFG Imperial Fleet.
Two battleships, 14 cruisers, dozen or so escorts.
I am currently looking to paint up a few Sword Frigates, a Cruiser and a Battleship (along with an auxiliary vessel). Methinks I will play a little with some basecoats and dry brushing and see what happens.