If you are constantly going low at night, you may want to consider adjusting your basal dose.
Depending upon what basal you are on, you could reduce it on the days you cycle. Tresiba can take 3 days to see a difference in the dose so there is no point adjusting that but Levemir and/or Lantus could be reduced on cycling days.
You mention a morning rise - this is more likely to be Dawn Phenomenon than a sandwich you ate more than 4 hours ago.
Regarding what to eat whilst exercising, I found the best thing for me was to maintain my levels during exercise by adding something slightly sugary to my water bottle (such as dilute fruit juice) instead of starting with a higher level which makes me sluggish. The level of dilution took a bit of trial and error to work out but if you are doing the same trip you have plenty of times to experiment.