No problem - I have found its easy to keep eels alive without water for close to a week if you take minimal precautions.
First - eels can live in salt water, fresh water or in air *if* they are *wet*. They will die in oxygen depleted water, or even in their own slime if it pools up 2 inches deep in the bottom of a bucket.
My approach. 2 buckets - classic 6 gallon pail as outer buucket, $ 2.39
eel bucket w/ top as inner bucket.
Aacquire eels - say no to water, say no to weed, just have them toss them in the bottom of the bucket. Now, make sure bucket top is latched and put it *upside*
dwon inside 6 gallon bucket. You have assured eels will neither drown or escaoe, both of which are very important. Eel's can get out of anything and can slither (I have watched it with my own eyes!) out of a closed lid by forcing their tail into the tiny crack, wedging it open and then slithering out.
Now as long as you keep that outer bucket out of sun and heat your set for at least 8 hours, probably as much as 12-24. Keep them cool, ie. outside. Put a board/cover/whateever on the outer bucket to keep coon's and skunks away if your leaving it outside.
Important. Every 12 hr's or so (less in hot summer sun) you must water your eels.
I take the iner bucket out, fill it with cool tap water, let the eels swim for a minute or two, make sure they are all alive, and then redrain it and replace it in the outer bucket.
I've kept eels alive 90 miles from the ocean for 3 days in mid July doing this; it should be cake for you this time of year.