I have struggled with access under the cabin sole and through the TAFG as well. With wiring I have usually been able to get the wires routed, sometimes using a fish tape, other times using existing wiring as a messager line.
But a few years ago I wanted to add a washdown pump. (You can read about the project if you click on Owners & Projects, then Owners Projects, E38 Washdown pump installation.) I mounted the pump under the galley, using the sea water pump through hull as the water source, and then had to run hoses forward to the anchor locker, and aft to the cockpit. This might have been a snap without the cabin furniture in place. But as it was the project was a royal PITA.
I ended up routing the hoses above the floor and TAFG just to make things easier. I was able to go around the stove, into the aft cabin, under the bunk to get aft. And I went forward under the port side and through bulkhead to get to the anchor locker.
So I guess my point would be that you probably can do what you need without routing the hoses through the TAFG - it just takes some time and work to figure out a way to route the hose. This would also allow you to mount the larger bilge pump wherever you want, not down in the bilge.