how wide does the ramp need to be and the holes for them to go through into the sleeping compartments.?
how big will the guinee pigs get.
will 180x60 be big enough.
can make it bigger if needed.
Hi and welcome
Your cage size will be generous for two guinea pigs but the more space the better - piggies that have space to run at full speed are happy and healthy piggies!
You will have to line the floors and lower sides ideally with something that you can easily wipe (correx, lino offcuts) as wood products will absorb pee and eventually smell.
Make sure that the ramp is shallow enough and has a rail (most cage/hutch ramps are too steep to be comfortable for guinea pigs and therefore accidents are not uncommon), and that it has some carpet or indoors doormat fixed to them with double-sided tape for better grip as you will have to replace the carpet from time to time when to gets very grotty.
You can find a whole chapter on cages - recommended sizes, bedding options, ramps, member galleries etc. in our very useful new owners guide collection which addresses all the aspects that new owners come across in practical detail that aim to answer those nitty gritty questions that most books skim over.
Here is the link:
Getting Started - New Owners' Most Helpful Guides
If you would consider adopting from a good standard rescue with quarantine/vet care, careful pairing for character compatibility and a pregnancy watch, then you can neatly avoid all the pitfalls that await the unwary. Piggies are babies only for a few weeks, teenagers for months and adult for years - by the time they have usually settled and got used to a home and to handling, they are generally teenagers, so you may want to consider whether a pair of piggies that are used to handling under adult supervision are actually better.
Guinea pigs are prey animals and not naturally born animated cuddly toys. They are also quite labour intensive in upkeep as they poo and pee a lot, and vet bills can pile up quickly with a serious illness or operation. They are by no means a cheap and easy children's pet. In good care they can live a normal life span of 4-8 years; and occasionally even a bit longer; so you have to have the commitment and interest to look after them for all the years after your children have lost interest.
Please note that as anybody can call themselves a rescue or a breeder without licensing or control (and the results can be sadly accordingly), we can only guarantee for the carefully vetted rescues in our rescue list:
Recommended Guinea Pig Rescues
New guinea pigs: Sexing, vet checks&customer rights, URI, ringworm and parasites
Boars, sows or mixed pairs; babies or adults?
Children And Guinea Pigs - A Guide For Parents