William,
Best of luck, and good for you for trying something new! I participated in my first ever NARAM last year, and it was a hoot! Good thing I wasn't trying to be competitive - I think my best finish in any event was 8th, with several events that ended without a qualified flight. So, with that caveat in front:
https://www.nar.org/contest-flying/competition-guide/duration-events/rocketglider-duration/ is where I started. It lists a bunch of plans, and I went with the Mediocre Fred. Model is build, going to try to fly it this weekend. Interested to see how it goes.
The one piece of advice I got from Tim at Apogee on this event is "Fly the field!". Backstory: I built one of Apogee's Stratus Gale rocket glider kits (
https://www.apogeerockets.com/Rocket_Kits/Skill_Level_5_Kits/Stratus_Gale) for the C rocket-glider event at NARAM last year. (That was my 8th place finish). I was asking Tim about flying it on a D10 (18mm AP motor) for this year's NARAM. That is where the piece of advice came in. He has flown the Stratus Gale on a D, and it boosted out of sight. That's going to be even more of an issue this summer where the humidity -> hazy -> harder to visually track rockets. His advice involved flying a bigger rocket that would be easier to keep an eye on.
Good luck, and hope to see you this summer. Maybe I'll even place 7th
BTW, I would suggest getting and building a Stratus Gale before trying anything else. I thought the video directions were great, and it walked me through a very complicated first glider build. The two things that were trickiest for me were 1) Airfoiling the wing and 2) the dihedral in the wing. It was a lot easier to go through that learning process with a kit and instructions, and then later apply that experience to a plan build. Just my $0.02.