Part of the plan is to post useful tidbits on vehicles here. So here's part two.
The rules are set up to encourage close combat. They did this by a couple means. The first was reducing the general effectiveness of firearms. The second big trick is the most useful shooty weapons are the vehicle mounted ones.
Since each Truk and Track can only have one 90-degree firing mounted heavy weapon people are encouraged to work towards more than one ride. Balancing it out against the number of fighters in the mob.
It is possible to have just one mega-Truk and a pile of Boyz. But a single well timed Scorcha shot and the game could be over before it begun. Or just one heck of a lucky hit, although unlikely vehicles can explode.
My plan is to start with a Freebooter "ship" as a giant trak, then expand with either bikes or truks to run escort. Or just go Gorkamunda. Still like the Freebooters idea more.