Elegant Degenerate said:
Do I want to ride exclusively below LT for a period of month(s) before I look to add higher end work?
What is the best way to do base training? and how long do you do it before working on other areas?
Answer to the first question is "no", though most elite cyclists do actually spend >90% of their training well below LT.
The goal of base-training is to: build enough endurance so that you'll be comfortable completing your race distances, and to get to about 90% of your peak fitness without becoming mentally stale. If you start out too early with structured, interval sessions then you may (almost certainly will) hurt your enthusiasm for hard training sessions, like intervals, later in your cycling season.
As long as your base training is enjoyable, you're recovering well, and you are seeing gradual improvement, then it's probably working OK. The length of the base training period depends on when your first really-important race is. Traditionally it takes about two months, after finishing base-training, to peak?
There is too much variability between us all to say what'd work the best for you personally. Here are a few points that I've found (through training and reading):
1/ Ride regularly. I find it much better to do 12 hours spread over 6 rides, in a week, than spread over 3 or 4 rides. It's common for rowers and runners to train twice a day (or more). Maybe we should be too?
2/ Most people have about a 50:50 ratio of fast-twitch (FT) and slow-twitch (ST) muscle fibres. (Though I'm more like 20:80 .)
3/ FT muscle fibres can produce a lot of power anaerobically (means "without oxygen"), but their aerobic performance ain't that flash (initially). Endurance properties of FT (i.e. threshold power) improve quickly with moderate to high intensity training though. But junk miles won't help much at all. (Some people claim FT can change to ST in humans, with a lot of long rides, most others say they don't.)
4/ ST fibres are very fatigue resistant but only improve relatively slowly, intensity is less important than training volume. This is why elite cyclists ride so many kms, they're maximising the performance of their ST fibres. Being able to race using more of their ST fibres, and less of their FT fibres, will leave the FTs fresher for when the selections are being made, and at the finish. But even ST doesn't benefit much from junk miles though. Generally, riding at >60% VO2max is recommended (maybe >50% initially, but should be more than 60% by the end of base training).
5/ If your training time available is less-than-ideal then you will need more intensity, to get the desired training load.
Since I'm mostly slow-twitch, I need quite a large volume of weekly training. The more I ride, the faster I get. I've tried training like the guy in the following article, for two seasons, and it didn't work that well for me:
He can max-out his heart-rate (HR) whenever he likes. When I'm really fit, I can't. I can't go anaerobic for long enough to get my HR all the way from threshold (~175 bpm) to max (204 bpm). In races and competitive group-rides (and running) I can get within 10 bpm, but never in training, unless I'm unfit (since lower VO2max).
Ideally you'd train like a pro, 600+ km/week. But if you have a similar physiology to the guy in the link, you could probably get very close to your biological peak with not many hours/week. I doubt that he'd see much year-on-year improvement though.