I'm trying to go off gid.... and questioning if its worth it to go the propane route or pay the monthly cost of natural gas. My plan was to build a super insulated, passive solar, and wood heated home. With propane boiler as a back up heat source and hot water supply and a propane range and maybe even a propane clothes dryer. Solar panels, batteries and a back up generator for electricity, or should I get the natural gas hooked up and get natural gas appliances ? The gas line is at the property edge.

I'm kind of doing the same thing as you, only in the maritimes where my wife's family resides. Like you, I'm considering propane, however I don't really consider it to be "off grid". We have drilled a well, have an approved permit for a septic system, and have planned for solar electricity as well as some passive solar heating to go along with a wood stove. I'm personally thinking that for our system, a largeish propane tank to service redundant heat, hot water, a gas stove, gas dryer, bbq, and back up generator. Clearly, I am not planning for independence from modern services. I believe that I have set myself up for a quick transition to independence should it ever become a necessity. I just don't think that I see the point to sacrificing modern amenities between now and the unlikely time that they will be unavailable to all. If I do find myself lost and wondering about the hand basket that I'm in, I will just have to figure it out. Where I'm building, natural gas is not an option. Most folks out there use wood heat and oil heat. We are about two kliks from the nearest power pole as well which I think is great. It serves as a discouragement for future neighbours.

If NG is available to you it's generally cheapest to use it. Assuming it's not prohibitively expensive to run it in

It can be off grid because one can always find a filling station that doesn't ask questions if you're filling the small bottles.
If you plan on having a larger bottle I suggest having it on a trailer your daily driver can pull and finding a place to have it filled that is not your BOL. This way the delivery truck has another address to report. In this case you may need to be creative or just look for a supplier who just wants the sale.

Any furnace, stove or BBQ that uses Natural gas can be converted easily to propane or visa versa.

As an emergency backup if SHTF propane is an excellent choice. It is still less $$ than natural gas or diesel and has an unlimited shelf life. Plus there are many sizes of bottles available so you can have a huge source, several smaller sources or a combination.

Indeed propane is an excellent backup. Plenty of RV's have heaters, fridges and stoves running off propane and can probably be found relatively cheap. You can get propane and NG lights as well.
I've never seen a natural gas refrigerator but I see no reason you couldn't have one.
A clothes dryer is still going to need electricity but generators run much cleaner on propane or NG than anything else.
I think NG is a bit cheaper than propane though.
Your local building code may not be too receptive to have you completely off grid, I get the feeling they like you be be dependent on their services.

" I get the feeling they like you be be dependent on their services."

Sounds pretty fringe to me. Are you sure this is in the right forum?