It's entirely up to your personal preferences but if you already have a Lee press, why not look up the Lee hand held press????
Then you won't have to carry a bench around with you and you can put everything you will need into one of those cheap plastic tool boxes. Mount your powder measure on a block of wood, or make up a powder measure from a cut down case that will hold exactly the charge of powder required.
I know it's off topic but I went the same route you are suggesting and in all honesty, it was a pain in the butt.
I just couldn't find a bench that was easily portable that would stand up to the levering of a standard press that didn't move all over the place.
I did see a very handy looking metal tripod arrangement that was welded up and drilled to accept a standard vise. The tripod arrangement makes it easy to balance but there is only room for the vice and nothing else. IIRC, it weighed around 20+ kilos.
To show how good the hand held Lee vice is, I used it for Hunter Bench Rest match loading and I can't blame anything on the vice. That little vice, which I still use on occasions, like extended gopher hunts, has loaded several thousand, very true rounds of 308win, 223rem and 6ppc.
Cost is under a hundred dollars for the whole kit.