Training without a race on the horizon
It has been over three months since I last raced. Two months ago I was supposed to race my 6th marathon, but it got postponed. Covid-19 has canceled or postponed (almost) all races recently. The likelihood of fall races being held remains low. Having one or several races on the horizon gives a sense of purpose to the training you are doing. You have a point to work towards. So, how do you train in these uncertain times? When you don't know when your next race is going to be?
Personally I have been focusing on building my base. Increasing mileage by running easy and long, then slowly introducing some faster workouts. Two weeks ago I ran over 100 miles total for the first time ever. Additionally I've been running consistently and well for 8 straight weeks, something I don't think I have done outside of the weeks prior to a marathon in peak training.
I'm currently training as if I don't have any fall races scheduled, despite the fact that my spring marathon got moved to the fall and I signed up for another one already too. If they do happen in the end, the training I do, even though it's not marathon specific, does still prepare me for running the distance. So I can still run the marathon, even if I haven't done the race specific training usually done leading up to the race.
Process goals
Having a race on the horizon allows you to set a performance goal based on that. But now is actually a great time to learn about process goals. They can be focusing on increasing the number of days you run or the (average) time you spent running. Perhaps adding a strength and mobility routine to your training could be a valuable goal.
Doing a (solo) time trial is a good way to still experience some parts of racing. Pick a race distance you like and run it as fast as you can. Sprinkle some time trials throughout your training plan if you like to spice things up. Just don't add too many longer time trials in close proximity to each other, because, like actual racing, these time trials can be taxing on your body. Also note that during a time trial you miss some of the race-day adrenaline and crowd noises, so it is normal that the times from your time trial are a little slower than actual race results.
Long term focus
In the past I found myself continuously focusing on working towards the next marathon. It was exciting, but obscures the bigger picture. It takes years to develop your aerobic base. I did things to try and improve my next marathon time, regardless of whether it was the "optimal" strategy for the long term development of the aerobic system. The base phase was a way to "fill the time" and didn't get the proper attention it deserves.
Right now you don't really have to worry about goal paces per se. Focus on the training paces, the easy runs, tempo runs, steady state runs and leg speed workouts. You can use the McMillan calculator to find the specific training paces that you can use based on prior race or training results. These training paces are determined in such a way that by following them you should see improvements in your fitness. Doing (bi-)monthly time trials, for example, allow you to measure progress and update your paces accordingly.
Enjoy the journey
Above all, now is a time to find out how you can make sure that the process, the training, excites you instead of only the races. The race, in the case of a marathon for example, is only a few hours. The journey leading up to it is so many times longer. Experiment with what works for you.