Most propane companies will come test the tank & lines, do the NG to LPG conversion on your appliances and any new plumbing that's required; or at least will give you recommendations for qualified techs who they've worked with before and do good work. It's best not to DIY gas unless you know what you're doing.
If you have someone come out to do the work, you may want to consider having them plumb independent lines for other appliances like water heater, dryer, additional heaters, and
your outdoor grill (lots cheaper than those little tanks!). It's less expensive and less hassle in the long run to have them do it all at once with appropriate shut-off valves, and then you can hook up appliances if/when you get them without needing to get more work done. Definitely spend the extra money to have them install an automatic "earthquake" shut-off as well so that the main line shuts down if the tank gets slammed... my tank got rocked during a hurricane which caused a leak in the line, luckily outside, but a leak like that inside could have been fatal.
When I lived near the Outer Banks NC, my range, water heater gas logs and wall heater were LPG run off a 500 bulk tank. I only had to fill it once a year in September (right before heating season) and never ran out, not even the year that it was below freezing for a month solid despite that 100 yo farmhouse having no insulation at all.
According to the
US Energy Information Administration, residential propane is averaging around $3 a gallon this heating season in NC. Most delivery companies offer some sort of discount for buying in bulk, buying by subscription plan, and buying during the off-season.
