Yeah, when providing advice, I find it’s generally better to assume less experience/knowledge than more, particularly when safety is at stake.
Any van worth its salt will have been built with plenty of anchor points in the cargo space. Normally, these are placed at multiple heights and lateral locations in the cargo space. Some of these points will also be compatible with bracing bars, or as you have found useful in your trailer, the ever useful 2″ x 4″ (or even better, custom made shapes, if one is feeling carpentry-competent!).
I particularly like pallets to put a machine on if they’re available. The wider base (assuming conscientious application of strapping) just makes moving the machine a bit more predictable (also partly due to the extra weight of the pallet). Also adds even more points for extra strapping low down, and the higher coefficient of friction between the wood and most surfaces, attenuates sliding a bit more (eh, every little helps).
I’m also a fan of pallet trucks, over engine hoists, where possible, less swingin’ rock and roll! Three machine skates can be very efficient too, but require a very watchful eye. Steel bar as rollers are also a reliable technique, but again require extra vigilance and are a bit of a PITA, in my view.
Obviously very few of us are lucky enough to have nice smooth, hard standing type routes from starting location to destination position, but sheets of 1/2″ or 3/4″ ply can help where the route is uneven or soft, but basically flat.
To be fair, as hobby machinists, having a trailer handy is very useful (not just for machine moving of course), and is a hell of a lot cheaper than hiring vans.
However, I do have a bit of a learned nervousness with trailers, as my first experience of driving with a trailer was as a student, helping a friend move a 13′ high, welded final year art project from Manchester University to Portsmouth, on a very gusty and rainy day (well obviously, Manchester, but the inclement conditions lasted the entire journey, it was at its worst on the M5).
Let’s just say, by the end of the journey my hands were aching terribly from my terrified grip on the steering wheel! I was still feeling it days after!
Eh, the blithe over-confidence of youth!
Still and all, if one hasn’t driven with a trailer containing a heavy and valuable item attached to the back of one’s car, I’d say it’s better for everyone (including the poor buggers surrounding one on the motorway!) to not have that as one’s first lesson!
I may be open to a not entirely unfair accusation of an over-abundance of caution, but that’s just the way I roll.