In the UK people use both both methods, usually depending on where they launch.
Many of the places I would launch in the South of England have Gravel "Hards" which are basically areas of sloping shingle but with limited or no vehicle access, so the boat has to be pushed by hand over the gravel. The launch trollies are lighter making this easier and there is the advantage of not getting the road wheels and bearings submerged in salt water. Having said that many people do manage with just a road trailer, I'd advise using Bearing Buddies to keep the water out, and never put hot bearings in the water.
I bought a second hand combi trailer off FB which is designed for a longer boat but means I can still use the bike rack on the back of the van.
A couple of photographs to give you an idea of the set up.
The width issue isn't so much clearance for the hull as clearance for the launch trolly wheels but I've seen people use flat bed trailers with the trolly sitting higher, clear of the trailer wheels.
We all have removable front castor wheels for our launch trollies which make life much easier. The trick is to have the boat balanced on the trolly with very little weight on the handle. This makes it so much easier to move around. The transverse support needs to be just behind the central bulkhead/forward end of the side seats.
My draw bar is quite long which adds plenty of weight at the hitch, maybe 20kg. I drive about 40 miles each way to my favourite launch spot and she seems to be very happy at 60mph.
The overhang isn't a problem, just make sure you put any heavy items up forward, or better still in the car. In the UK /EU new trailers have to have the lighting board attached to the trailer not the boat. Check your regs.