new plugs...now misfiring on cyl 2&4, and far from home

My 2010 Prius has 210K miles on it. For some time, it would give the classic knock/misfire on startup, but only on the first start after 2 to 4 weeks of sitting idle. A little coolant and a quart or two of oil were usually consumed between 10K dealer service.

I had the dealer install new plugs about 500mi ago, and now it's misfiring for 5-10sec seemingly every time the engine starts, and maybe even when the engine activates in the middle of driving.

OBD cods are 300, 302, and 304 (cylinders 2 & 4 misfiring). The "check engine" light is on but not flashing.
I'd suspect the head gasket is going or the EGR system problems are finally catching up with me, but the misfires got dramatically worse just 500mi after the new plugs.

I have a service appointment in a few days, but am 500 miles from home and the dealer. I'm tempted to limp home to the dealer. If the check light starts flashing, I'll stop & get a tow to a dealer along the route.

Any opinions on whether it's foolish or reasonable to try to make it home to my dealer?
I suppose another option is to have a local dealer look at it before I make the trip, but at least I trust my guys at home (haha).
Thanks....

 

Thanks. That's all I was looking for...an opinion and more info. I'll decide, and take responsibility for it.
It's Sunday, so the plan is to call my home dealer and the local dealer on Monday morning, and see what they say.
Wouldn't a head gasket failing on non-adjacent cylinders be a bit unexpected though?