Border collie 11yrs -advanced lymphoma (Lymphosarcoma) -now bloody diarrhea- Hemorrhagic gastroenteritis (HGE)???

I am posting this as I am desperate for ideas on what to do for our terminally ill boy... I would love to hear if anyone else has been through this with there beloved pet???
On Saturday 20th Dec Rocky was diagnosed with intermediate to advanced Lymphoma/Lymphosarcoma. It's through all his lymphnodes.. The prognosis is not good unfortunately, the vet has given him 1-2months at best. .. We considered Chemo, however with his age, stage of the cancer and also a gold ball size growth we have decided that palliative care is the only option for him. This is day 4 of his Macrolone treatment to make his last weeks comfortable for him. Last night however he has had watery/bloody diarrhea, with blood clots. He seems to be in good spirits, considering his cancer, and panting (due to growth in lung). He even pricks his ears up when mention some of his favourite things..
We really need to take him to the vet, but live on an Island and would had to make a significant trip in the pouring rain, taking a car, then ferry, then walk to another car and then drive 40mins we don't want to stress him anymore than we have to. We would like to keep him home for another 2 days, so that when the island vet is open, she can come to our home and put him to sleep in his own home peacefully. My only worry is that this bloody diarrhea could be from Hemorrhagic gastroenteritis (HGE).. We don't want him to suffer, but we really don't want I stress him out in his last hours by travelling and then to have him put to sleep in a cold unfriendly vet consult room.. We don't know what to do!!
Rocky has been such an amazing best friend to all of us in the family. It's heartbreaking and agonising to watch your companion and bestfriend knowing that these are his last days This Christmas has been a particularly sad one for our family.