How many days boondocking?

I have found the two most limiting factors are the battery power and grey water. A 20lbs. propane tank last me most of a season, with a mix of dry camping and hookups. If you have a spare, they are easy to change. Fresh water can be refilled with a "jug". I have a 6 gallon fresh water container that I use to refill my tank when needed.

However, there is a finite amount of grey water capacity. If your tank is 35 gallons, that's all that will fit. You'll have to dump before you can use more fresh water. There are "totes" that some use to extend usage. Showers account for the most usage. Take "Navy" or "submarine" showers - wet down, turn off the water, soap up, turn on the water and rinse off. Shoot for 5 gallons or less per person.

Black tank - I can't imagine that ever completely filling. Only the toilet goes in there. That said, I always dump it when I dump the grey tank.........why not?

Battery is widely variable. I have two 12 volt batteries and usually have no problem going 3-4 days, with reasonable use, in mild weather.

So, to answer your question - 3 days would likely be the maximum for two persons (assuming you each shower daily). However, your mileage will vary.

Agree the rate limiting step is the grey water. tank  Most states do not allow grey water dumping on the ground.  We fill a grey tank after two days with showering and dish washing.  We could more than double that by taking navy showers and putting a pan in the sink to catch the water and then dumping it down the toilet. We add water to the black tank when we start our trip and after five days never filled it up, so putting grey water into black tank is a good idea.  I wish there was a switch to do that.  Instead of 30 gal black and 30 gal grey it would be nice to have 30 grey and 30 grey/black mixed.  I should put that on the wish list post!

Agreed that the gray tank is the first to fill. Using a dishpan and dumping that in the toilet to go to the black tank would help. Navy showers or simply sponge baths with a sink full of water for daily clean-up and then navy showers maybe once or twice on the trip can help. Some Camping World locations have dump stations as do state parks. If you stay at a state park, you could top off the fresh water and drain the gray water before you leave. One waste of water is running the hot water and waiting for it to get hot. In our 179, it wastes about a gallon of water given the distance between the water heater and the sink. We found that it makes more sense to heat some water on the stove for dishes. For the bathroom, it can't be helped as I don't like cold showers.

Propane will not be a problem. Unless you are running the furnace excessively every night, one tank of propane would be more than enough to get you there. The refrigerator does not use much at all. The stove is not run constantly and so does not use much. Hot water can use it if left on all the time. OTOH, if it is on just for heating water for a shower, and if you heat water on the stove for dishes, you won't use much for that either. If you have a Costco membership, a number of Costco locations have propane at a good price. If you are a Good Sam member, Camping World has propane at a good price also.

One limitation is your battery power. Since it looks to me like you will only be staying overnight, then it looks like this will not be an issue as the battery will be charged every day as you drive. We have dual 6V batteries connected in series for 12V since I use a CPAP machine and since we have stayed at some state parks without electricity. We have gone three days before I fired up the generator to add some power to the batteries. I could have gone more, but we wanted to use the microwave anyway. I don't know about your Tow Vehicle (TV). Depending on the TV, you may or may not get a good charge if you run the refrigerator on 12V while on the road. My experience was not good so I run the refrigerator on propane unless I have shore power (120V) available. If your TV has a high-output alternator and your wiring is adequate to get sufficient power to the R-Pod to both run the refrigerator and charge the batteries, it is okay to run on 12V. If not, then it is better to run on propane to make sure your battery is charged when you want to stop for the night or stay somewhere for a day or two if shore power is not available.

One other alternative to showers is to use wipes like Assurance Personal Washcloths for in-between shower clean-up. You can find them in drugstores. These are like ones used in hospitals and can save a lot of water. There are some dry shampoos that can be sprayed on and brushed off for quick hair clean-up as well.

Thanks guys.

Already looking into Solar. Couple of 100 watt panels should make a big difference on the battery.

This is I think going to be a balance thing between me and my wife.

I like it wild, she likes it mild with comforts.

Still if we can get 2-3 days quiet someplace, then roll some road, find a state, city park with dump, showers, and electricity. I might be able to talk her into looking for another wild spot. Or maybe not. We'll see.

At least I have an idea of how to plan now.

Was thinking last night that we are probably going to want to roll through the big city's on sundays.
Less traffic, less hassle, and we can drive a little slower without annoying everyone else. By the interstate there are always places open on Sunday if we need something.

I'd like to stick to back roads as much as possible. But in places the roads just don't go anywhere but into the big city.  Chicago and Atlanta are 2 good examples.

Having done this with our 177 since 2011 we have found out we can be quite stingy on water use.  As others above have stated, your propane will last a long time (we carry a 2nd on on the tongue), never fill at a Blue Rhino or similar as you only get a 75% (15 galloons)for your "filled" tank for more money than if you go to a hardware store that sells by the pound and will fill your tank to actual full (20 gallons)."  We normally expect 3-4 days per battery (12v  group size 24 deep cycle) when the weather is cold at night (30-mid 40's).  We also carry 2 batteries on the tongue of our 177.  In warmer weather, battery life is not an issue as when we move locations, the TV will charge your battery.  Water usage, we carry drinking water in 5 gallon totes, beside that which we carry in the tank.  For extended trips we carry 3 totes (15 gallons) and consume 1.5 gallons/day for the 2 of us.  The 30 gallon tank will last us 1 week, yes, we do sponge baths or use a local stream or lake if possible for total washes after hiking.  Enjoy your 189.