Here are a few issues to consider when searching for your off-grid paradise:
Most off-grid properties are remote, which likely means far from town services. As you consider a parcel, consider if its remote location will necessitate excessive driving.
If the property has reliable grid power at its edge or nearby, consider tapping in. Build your home as if you will be off-grid—that is, with the sensible energy efficiency of an off-grid home—then hook to the grid and install a grid-tied system to offset your utility electricity consumption. You will spend less, reduce your impact by letting the utility take the place of a backup generator, and have less maintenance and battery replacement expense.
If buying a home with an existing RE system, consider having the system professionally inspected, just as you would have the home inspected. An existing system may have served its former owners well, but may be totally inadequate for your needs, or antiquated and difficult to maintain. Few home inspectors are qualified to evaluate RE systems; use this opportunity to get to know an installer to see if they are right to upgrade the system.
If buying an existing on-grid home, it is probably best to leave it on-grid. Taking an existing home off the grid is a difficult and expensive task, as many prior decisions—about siting, appliances, water supply, and heat, to name a few—were likely made without consideration for future off-grid possibilities.