Some are stiff as pipe, and the cold doesn't help at all. If it is PVC hose (white) you may either need a heated work area or to wait until summer.
I've worked with a bunch of sanitation hose types--5 on my boat as part of a review--and I've posted some of the lessons learned:
Sail Delmarva: The Easy Button
The full article, focusing on long-term durability with sewage exposure, will be out soon.
If you somehow manage to bend the hose to reach the required spots, there are a few things to consider:
* The hose may simply kink. Maybe not right now, maybe in a few weeks. Don't force it.
* If it is tight going to the bottom of a Jabsco head, good luck changing the joker valve in the future. You may get it on, but you will play hell getting it to seal if there is much bind. I don't know about other models.
* As for heating the ends of PVC hose to get them on fittings, I had the best luck with dunking them in a pot of boiling water for 20-30 seconds. But I basically dislike the PVC hoses; I only use it for vents, since it's generally all that's available in 5/8" and 3/4".
You can use PVC fittings. Sea/Land and others make sanitation hose specific fittings. They will never permiate and plugging is not a problem; that always happens in the joker valve, as it is much smaller.
Before I considered cutting holes I would try a more flexible hose. Raritan Sanigard is quite flexible, and any of the rubber sanitation hoses are easier to work with than the white PVC hoses.