For long term boondocking a few 6 or 7 gallon containers may not be enough, and I for one, would not want to have to lug them around. A 55 (or 35) gallon drum can be secured in the bed of your truck, filled and gravity drained without ever having to move it.
As stated above, you do not need to use a large hose when using a macerator pump. The resulting effluent will be fine enough to pass through a 1/2" inch hose but use 3/4" to be safe.
I have a 35 gallon gallon black tank and can go 10 - 15 days before it needs to be emptied. My plan is to use a macerator pump and 55 gallon drum as outlined below. This should allow us to extend our boonie time to at least 27 days and possibly as much as 40 days!
2 more new food grade barrels will be set up the same way for fresh water storage giving us 210 gallons (100 gallon tank in toyhauler) of fresh water. I will use a 12v pump to transfer fresh water from drums to on board tank.
Open top plastic drum+
Bung wrench+
Bulkhead fitting for 3/4" faucet+
3/4" ball valve faucet=
TO BUILD:
Remove top.
Install bulkhead fitting at bottom of upright barrel.
Install ball valve faucet in bulkhead fitting using Teflon tape.
Reinstall top.
Place upright in pickup bed and strap down.
TO FILL:
Remove one of the upper bung caps with bung wrench.
Place outlet end of macerator pump 3/4" hose into drum (tie or bungee in place so pressure does not make it jump out).
Turn on macerator pump and transfer black or grey tank contents into drum.
Flush hose with clean or grey water.
Remove hose when done and reinstall bung cap tightening with bung wrench.
TO EMPTY:
Open tailgate.
Hook 3/4" hose to faucet and run out open tailgate.
Place opposite hose end in dump receptacle.
Use bung wrench to open one of the bung caps to provide a vent.
Open ball valve for gravity flow into receptacle.
Flush barrel and hose with fresh water (if available at dump site)*.
Reinstall bung cap tightening with bung wrench.
* If you don't flush the drum sediment will build up and plug the faucet, so flush ASAP if you can't do it at the time of dump.
There are many sources for drums and accessories. I have used Baytec Containers with good results.