I have already done what you are thinking of doing - using guttering for the longer ramps. However some things for you to consider:
1) If using inside then use guttering with sides for their safety, as the piggies do change their minds and turn around halfway up, or sometimes get spooked about nothing and charge up or down and it would be dangerous for them without sides.
2) If using guttering outside then you will need it so predators can't get to them when they use the ramp moving between cage and run - so would advise using fully enclosed guttering instead. However this will need to be wide / large enough for the piggies to move up and down safety without getting stuck and allow them to turn around if need be - depending on how long the link between the two would be.
3) To make it easy for them to run up and down use carpet tiles cut to size and put in the base of the guttering ramp. Thier claws grip this nice and easily and they won't slip. Plus for cleaning you can velcro it to the ramp, so you can remove easily. I don't clean mine that often as I find that my piggies do not sit on the runs and never wee or poo on there, so I only clean the carpet tile strips every few weeks.
3) The run you are planning on using is fine for inside, but would suggest not that safe for outside. The non-secure roof would not prevent a fox or a cat from getting in there, and probably not a hawk either. Instead I would go with one of the Zooplus ones with a removeable wooden roof. For example the one I have is:
Outback Classic Outdoor Run - 4 Sided
Here is a picture of my cage setup linking the cage to the run, but without the roof on, because my setup is inside:
I also built a central platform out of an old shelf, which bridges the gap between the cage and the run and links the two ramps together, whilst sitting in the opening for the side door of the cage.
I hope this help with your thought process, but feel free to ask any further questions and I'll help if I can.
