L2 is great for newbies.
The biggest challange with them, is to hook them to the sport. Best way to do it, enjoyable sight seeing rides.
There is no need to push over L3, for someone that is riding her first 1000mi, in first year of training.
Just go out there and meet pure pleasure, under the sun, with few ez hills, and maybe one or two more difficult.
A drug gets released in the body, when doing L2. I don't know the name of the drug, but newbies got to experiment that. For newbies, L2 is the best way to train Lactate threshold, as it will have a favorable impact on the whole cardiovascular system.
Tempo may sometimes be bad, it may make them feel uncomfortable.
Newbies should learn how to log, as early as possible. They will have a motivation out of their written improvement.
When they group ride, they will be naturally intested to join faster pack, especially if their friends are in the pack. Then, they'll be ready for more hardcore workouts 😄
So Topcat, newbies should keep tuning up the engine for as long as you want. And for the rest of their career if they want, there is nothing wrong with that.