I have a diabetic cat – his life is no different to how it always was – he is free to roam and do his own thing. We would have a problem if he decided not to come back for more than 12 hours but then, things die of all sorts of other issues. I met someone else with a diabetic cat who had been on insulin for 2 years + and she said he was no different to how he had always been. I have also met someone with a diabetic horse.
I think we find it a bit intimidating and harder to adapt to medication issues than the animals do as they have no preconceptions or hang ups.
The injecting etc is worrying for about the first fortnight, then you get used to it and stop worrying about it so much after that.
As long as you can find somewhere to store insulin its no worry to take your dog I would think. Why is someone suggesting he can no longer camp or play on the beach? It could just be suggested for his initial adaping time when there is an increased risk of a hypo? It takes the vet a while to get the dosing correct.
Someone put medical care of pets into perspective for me once – said that I should worry less as the illness the pet has as it might not be the one that kills it anyway – other diseases, road accidents etc. Every day we humans go outside or even get out of bed we face some risks and so do pets. We could keep our cat indoors just in case he wanders off and gets lost/looses an insulin dose. But you have to think ‘would I want to live like that if I was the cat?’ So we let him out and he has higher risk of problems or death, but he has a fun life and thats better than a miserable one.