I’m coming to cycling from long distance running and am an absolute beginner.
Due to Covid, there was no race I was aiming for when I signed up to TR at the beginning of August.
I started with a Low Volume Gran Fondo, and will complete this middle of December.
I’d like to do a outside ride once I’ve completed this first training plan, but am not sure what sort of distance I should aim for. My longest ride before starting the training was 50 km.
I would suggest using Plan builder, it covers 90% of use cases pretty well. Right now it will auto-update when you add your races and planned time-off (it did not work that well in the past).
I predict that the plan builder will suggest you to do some Base plans first. Do not resist, they are in no way easy and a necessity so that you can add specialized training on top of that.
I also suggest staying on Low Volume and either adding outside rides on top of that or replacing weekend workout with long ride. Aim for time, not distance and do as much is enjoyable.
Sorry, maybe I should have been clearer.
My question is as to what outdoor ride (duration) I should do after I completed the first plan.
I entered a ‘made up’ race when I created the plan.
I think you should do whatever you want. You must have an idea of what you’re capable of. So my suggestion is plan a long, challenging ride, with an option to cut it short if you’re struggling or not feeling the love. A larger and smaller loop that make up 100km or 100mi for example. You’ll be surprised how much stronger you are after a solid, stuck-to block of structured training. If you’ve not been outside and have seen your FTP go up, be careful though. I came to triathlon from running, hammered out two or three months of TrainerRoad over winter, and when I finally went outside was much faster than before, with zero bike handling skills… Followed by a week in hospital, two surgeries and seven weeks off. 
Ahhh, yes. There bike handling skill to consider too 
Guess me point was that for running, you picked a distance, a desired time, and the time avaliable between your decision to train and the race. That determined frequency and intensity of the training.
When I entered my training plan, there was no question as to what the expected distance was for the race (even the pretend one).
It will have asked you for an expected duration though - that is much more relevant in cycling since a 100km flat race will be very much shorter than a 100km mountainous race and probably again than a 100km MTB race…
In any case the TR plans focus on training the required energy systems - it’s possible to do most of your training for a long event using only 60-90 min workouts (or all in a pinch, but not advisable!), although of course doing longer rides is still very useful training and preparation - especially getting used to being in the saddle for a long time, but there’s other training benefits you get from a 4 hr ride that you don’t get from 60-90 minutes. To get used to being in the saddle for long periods, you really need to do it.
Having said that, in your position, I’d just start small and work up if there is no pressure. There’s no point going for a 100km off the bat and being miserable after 4 hours is there, start with 1-2 hours and build up. As a long distance runner you are probably used to going for 4 hours, but if you really are an absolute beginner cyclist you could discover bike fit problems, kit issues and all sorts over longer rides.
With running it is much easier to predict time from distance because drag counts for much less and your pace is less variable over changing terrain. But with cycling drag and rolling resistance are such huge variables that it is very difficult to predict the time it’ll take to go a certain distance.
If you are very unsure then I might plan your ride in either a ‘figure 8’ pattern or a loop that you know has multiple shortcuts as bail-out options.
For the figure 8, maybe choose a distance that you are pretty sure you can complete (like 65k) that starts and ends at the same place. Then have an additional loop of ~20k that you can do after that if you get back to your house (or car or wherever) and you feel like you still have some gas in the tank.
For the shortcut example, here’s a pic of some routes I frequently ride:
Both options are good choices if you are unsure that you can complete a longer stretch distance.
Running a 50k is going to probably feel far harder than riding 100 miles, but take roughly the same amount of time. My GF went from ultra running (recently doing a 50 miler) to cycling and did a 100+ mile bike ride within months and didn’t even feel worn out in the slightest.
If that helps put anything into perspective.
I think you have that backward…Riding 100 miles will probably be much easier than running 50k. (Though I’ve never run anything close to 50k)
Oops
Hmm, just checked.
If you create a new training plan without an (actual) event, it doesn’t ask you for the duration.
Yeah, I think you’re better off sticking a fake event in there, as that asks for a duration, and the plan will work it out, e.g. rolling road race with a duration of 6 hours.
I guess my first error was to not have a race (even a fake one) as I’m now getting to the end of three months of training and my last week are three endurance sessions.
Going from what I did for running, there was always a taper week before a race, so assume that because I didn’t select a race, there is no taper.
Yes - you’re finishing in a recovery week there. You can just start another plan after that, or do a plan builder from scratch.
