That is an interesting dilemma.
How time / money do you want to spend?
Cheapest option is to find the supply hose. (Mine was 11 dollars), and relocate your existing regulator to the included stand. Use a little sealant to seal up the holes. (Silicon? I'm sure people have opinions on what's best for your material). At this point, your Bottle hose might be TOO long, so you might need shorter one. (So maybe NOT the cheapest option)
Easiest option is get a longer bottle hose. The bottle hoses appear are more expensive. (The 18" inchers I got were like 15 dollars, but I see on Campers world 30 inches for 20 bucks) (Finding those hose seems to be really hard, so maybe NOT the easiest option)
Expensive option is:
Thow away everything and do what I did (All of my stuff was broken, so I had to anyways). New supply hose long enough, to put a new auto change over regulator on the mounting bracket (Some of the regulators are already mounted), and two new short pigtails. I got 18", but if I did it again, I'd go with 12".
Here's the only supply hose I've found online:
Don't know if that's long enough.
I bought mine from a local RV dealer's part shop.
So what the RV Dealer taught me, Flare threads do NOT need LP pipe wrap (Yellow Tape). Pipe threads DO need LP pipe wrap. For me that ended up only being the regulator.
Don't forget to check with a soapy solution looking for leaks when you're done.