First long trip

May I suggest, that after dumping and after adding about 2 gal of water to your black tank, and when adding the degrading powder/liquid or packet down the toilet also add 2-3 caps full of Calgon liquid (available at most grocery stores or WalMart). This helps when emptying the tank as the water is soft and it all slides out easily.

We just returned from a month long trip out west and we have a 45-50 gal (I think)black tank and we emptied after each stay of at least 3-5 nights. A lot would depend on how much we used it - if we were out sightseeing all day or spending time around the trailer and using the toilet more. Some places we were stopped for a week others 4 nights.

It really depends how long you can go before black tank needs dumping. We can go quite a stretch without dumping black tank, but grey tank typically will need dumping after a few days anyway thus black tank gets dumped at the same time. Of course you will be dumping tanks at your last spot before going home unless you dump at home. Enjoy your first extended trip out in your RV, we find that there isn't much difference whether going out for an extended weekend or a couple of weeks at a time.

While you're at a full hook up site(with sewer) never leave your black tank valve open. You need some liquid in there to help the.. matter.. wash out down the line as needed. If not it will just cake in the tank and you will have to stick a hose in the toilet to clean it out

How many people will be with you ? And how big is your tank ??

Probably should dump the tanks right before leaving each site, sooner if necessary, and then put a couple of gallons back into each one.

DO NOT LEAVE THE DUMP VALVES OPEN ALL THE TIME especially the black one.
(Explanation if necessary.)