We laughingly tell people we could run a small hospital if we had too. Couple years ago our local hospital dropped off after just a few hours when their day tank ran dry. The entire county was dark. I'd rather not do that drill again.
I've seen many cut-rate installations (shoddy equipment) that outputs such ratty power that uninterruptable power supplies (aka computer UPSs) continuously trip offline. I don't have any idea how modern LCD/plasma TVs are handling such junky power. Not well I suspect.
For those that ask our assistance and with whom we interact our advice has consistently been to buy all the quality kVAs you can possibly afford and do it 'right'. Low speed engine, minimum 4-pole generator head, good controls (switching, output, engine systems).
Natural gas seems more problematic than LPG: in a storm event the system can be damaged or flooded and then take days to get back under control. Same is true for propane: tanks float off in a flood or get redistributed by a tornado.
For the size you mention, consider a gas engine-driven welder. Lincoln and Miller both produce nice high quality units with real copper windings, ruggedized, multi-fuel (convertable), and you get a welder to use otherwise around the place. Hardwire a 50-A male plug off a transfer switch and roll the welder up and plug in. Make sure the machine actually outputs 240-VAC in the form of two each 120-VAC circuits (120 from each 'leg' to neutral; 240 'leg' to leg') just like the grid.
Good luck and I hope you stay powered up.
/s/Stubbyie