>>1581631>I did 150kn in 8 hrs yesterdaythat sounds like too much
i don't think you necessarily have to "train" long distance as such, it's more about finding the pace that you can sustain (of course depending on your fitness)
speaking for myself, riding to work every day (about 30km roundtrip) was more than sufficient physical training. then on my first tour i had to learn to pace myself, keep the gear/resistance below a certain threshold, eat consistently, provision my power. if you overdo it, you will feel it with short delay. when you do, stop for a break, eat something, continue more slowly, and you will feel better just as quickly. don't fully exert yourself.
that said, i am still learning myself
tr:dr:
training might as well be short distance
long rides teach you how to pace yourself and provision your power