A Trailer every time. My Egli Godet Sport GT has a QD towbar, custom made for the bike very cheaply, fitted or removed in about 5 minutes. Full rear lights, flashers reflectors etc. Trailer takes all the weight apart from weight on tow hitch (which you can adjust by the way you pack the trailer) Rotating tow hitch so you corner exactly as on a solo. My trailer was designed and made by West Country Sidecars ( Phil Primmer) and is no wider than mirrors on the bike. You need to leave a little more distance for braking (but you won't be going mad when touring with luggage anyway) and acceleration is (very) marginally slower. My fuel consumptions were virtually identical to no trailer figures .Can be secured to a lamp post etc by chain and lock if you wish to ride off somewhere or take a hotel room
My trailer has a locking hitch while on the bike, a spare wheel and a prop stand, on the hitch bar. Unhitch, kick down prop and your bike is immediately unloaded.. Box itself has locks and extra catches plus a rack on top for anything you want to use quickly eg waterproofs.
Same trailer goes on my BMW and the number plate on the rear of trailer is turned over (Egli No. one side BM No. other side)
For fun the trailer is called "The Vincent Black Box" in Black Shadow script.
You very quickly get used to a trailer, and ride almost exactly as you would on your solo, The only thing to watch, is if filtering leave extra length before cutting back in, Bulky but light items . such as sleeping bags are easier to pack in a trailer , Until you try .it don't knock it!
See Philippe Guyoni's book "Vincent Motorcycles The Untold Story since 1946" for pictures and comment on my Egli/trailer combo. A Trailer Every Time
I know one picture below shows something on the bike carrier, but this was exceptional. (see last paragraph) The panniers are on so that if you stop for whatever, just shove your leathers, gloves etc in them and explore, unencumbered. SIMPLES!!!
Now, keep this to yourselves, Gentlemen, but if you are travelling with a Lady, there is always enough room for 3 ball gowns 14 pairs of shoes and a large Make-up bag. But I would not advise wrapping your spare Magneto in her best underwear There is however enough room for it all!!