I don’t have a recumbent. However, I have talked to such riders over the years. They make it up most hills. In the river towns there can be a few very steep hills where I have seen all types of riders walk up those very steep hills.

Understand that. Better drag the trike then blow ACL.

I ride a two wheeled recumbent, so my experience is not the same, but may give you some insights.
I used to have lower gearing, but lost some when I went to electric shifting.
Recently I put on a 10 by 36 tooth cassette so the new ratio is 33 to 36. I hope you have lower gearing. I think we will have three hills at 10% the first day and a 12% on the last day.
One advantage you have over me is that you won’t tip over when going slow. I need to maintain five miles per hour to stay upright. So if you can keep pedaling you should be OK.
To practice for hills, try riding into the wind, or grind away in the highest gear you can handle. Get used to the higher resistance. We still have a few weeks to train.
The only other suggestion I have is to zig-zag up the slopes to “reduce” the grade. Just make sure that you are not impeding other riders. Good luck.

thanks for input. even if going 3mph i won’t tip over at least. Might not even be at that.

Been doing it for years, self-contained. No big deal. A couple years ago, on my way out to start RAGBRAI, on a 12% grade leaving the town of Lynnville, I got passed by an ant – a very motivated ant.

Last time I pedaled up a grade that steep, had a dog run over and start peeing on my back tire.