Okay, so you would just dump your ores into chests which means you would set up where you left the chests. That is not going around for days before setting up, it is mining in a limited area where you already decided you would stay.
Incorrect.
Just because you toss stuff in a chest doesn't mean you have to stay there. Rei's Minimap allows you to place waypoints. I would either drop a chest at the entrance to the cave I was in, or more likely dig straight up and put a chest on the surface and drop a waypoint.
That is assuming that I mined anything and everything.
You have 36 inventory slots. Assuming I didn't spend the time collecting string to make canvas to make canvas bags or make/collect wool to make forestry bags, I would only mine Copper, Tin, Iron, 1 stack of coal(never more than that on me at any 1 time), 1 or 2 stacks of nikolite&redstone, Ferrous, Diamonds, gold, lead and silver. Possibly Lapis but since I don't play with IC I have very little need for Lapis. Maybe some of the gems but those are easy to find and at best they would replace the stone pick and sword and the rest I would leave since they are so easy to get.
Out of those 36 slots, 2 would be picks, 1 iron and 1 stone. A stone sword. A stack of torches and any food that I collected. A furnace and a workbench. That leaves 29 slots to fill with mostly Iron, copper and Tin. Take away 4 for redstone&nikolite, 1 each for coal, lapis, ferrous, diamonds, gold, lead and silver. That leaves 15 slots open.
I would also have 1 stack of cobble for placing down when necessary along with 1 stack of logs.
That leaves you with a grand total of 13 slots open for Copper, Tin and Iron, with some minor variations if you happen to get lucky and find lots of lead, silver or gold.
There is nothing stopping you from placing a chest down out in the middle of nowhere and coming back to it later to retrieve the stuff in it. I personally travel thousands of blocks looking for a site to make a home. Sometimes I have stuff with me, sometimes I have nothing more than a pick, sword and some food and saplings.
On the vanilla smp I play on, I have a couple score of single chests scattered around the worlds from where I have dumped excess stuff when I was adventuring. People may or may not have found them over the last two years. If they were important enough for me to go back and get them I would have but I generally only took the valuable stuff with me, Iron, gold, diamond and lapis.