I don't think routines have to involve crying at all. Around this age, your LO is probably getting into his own routine. Maybe for the next few days, start writing down what time he takes his naps and for how long, seems hungry, is ready for bed, etc. You'll probably notice a pattern. Once you see that pattern, you can start working with that pattern to plan for naps, meals, bedtimes, etc. We never really had a predictable pattern for nursing as far as I know, but his naptimes were definitely predictable.
Once you determine his preferred bedtime, you can start a bedtime routine to help him go to bed at that time every night. For a baby as young as yours, start the routine about 30 minutes before bedtime. Read books, take a bath, nurse... whatever you want to do. Just make sure its calming. And you will probably want to close the blinds and turn the lights down low.
There is literally no reason for crying when establishing a routine. When DS was about the age of yours, I was able to write down a (flexible) schedule for our whole evening for me and my husband to follow. It was never on the dot, but it was within about 15 minutes. If everyone in your house knows the routine, that will help a lot.
You still need to watch for cues because just because they get on a predictable routine now, that doesn't mean it will stay that way. Within in a few months, he'll only want 2 naps intead of 3 (or however many you have now). So you'll notice he's having a hard time getting to sleep at night or going down for naps. You'll have to readjust and keep trying to get cues from your LO.
I think your DS is at a good age for a routine. Think of it as a routine, though, and not a schedule. Schedules are rigid, but routines are beneficial for everyone.