I echo what Tony Soprano said, get the steroid injection ASAP.

About 10 years ago I got PF in my right foot. Did all of the treatments listed in the above posts, including night splint/boot, ice rolling treatments, massage, anti-inflammatory meds, custom orthotics, stretches, etc. Did all of that stuff for about a year and a half. I did get a steroid injection a couple times (the docs say you shouldn't get them more than a few times/year as it could cause damage to surrounding tissue); the injection in the heel is super painful, and the injection site was very sore for a couple days. But after that, it was fabulous, no pain at all. However, after a couple of months, the pain returned and I'd repeat that treatment cycle. My doctor talked to me about having surgery done, where they go in and clip the ligament, allowing it to then "lengthen" as scar tissue grows back and reconnects to the bone. It isn't always successful and I was leery of it. Then my podiatrist recommended an alternative procedure called lithotripsy, via an instrument called an Ossa Tron. Insurance was reluctant to cover it but finally did. It is a shockwave treatment that "zaps" the insertion site where the ligament attaches to the heel. It sort of traumatizes/causes an acute "injury," which the body usually responds to and heals (PF is a chronic injury where micro tears keep occurring each morning after rest/healing during the night, and that is why it is so hard to get rid of). Anyway, this Ossa Tron treatment worked and I've been fine in that foot ever since. If you can get it down the road, it might be worth a try.

THEN, about 5 years ago I developed PF in my left foot. I started the various treatment cycles again, including the steroid injection, which again, was the only thing that worked. I'd had the condition for about 6-8 months, and then the strangest thing happened. I was playing tennis and went to plant my left foot hard to push off and go to my right when I heard and felt a loud POP in that foot. I went down to the ground immediately, scared of what happened. Long story longer, I went to the ER and MRI showed that I had ruptured the ligament, torn from the bone. However, that wasn't such a bad thing as in effect, I had "performed" self-surgery, and it really wasn't all that painful. I was in a walking boot for a couple of months and after that and to this day, no problems. The ligament had healed/tissue lengthened and it was fine.

Anyway, sorry for the long story. But if you really want to go on your hunt, I say get the steroid injection about a week to ten days before the trip and you will be fine. Just double-check with your doc to make sure he doesn't think you could further injure yourself. I've had these injections in my heels, knee, thumb, elbow, and shoulder, and they always take the pain away for a couple months, at least.

Good luck and keep us posted on how things go.