I know it has been a while since anyone replied to this topic - but I wanted to add to it. My 78 pound, 13 year old Golden could not do the stairs anymore but refused to stay downstairs at night. I even tried putting up a gate and she would knock it down, drag herself up the steps and fall - I couldn't let that happen. So I had a used Acorn Stairlift installed - in place of the seat I have a heavy piece of counter type material ( it was actually the cut out from a friend's kitchen counter where the double sink went!). The whole think cost me $1500, $1300 for the used stairlift with installation and warranty and $200 for the adaptations. It is worth every penny.
I wanted to post this because when I searched I couldn't find anything at all anywhere with ideas for a stairlift for a golden retriever and I know the ideas would have helped.
Hope it helps someone else.
I used decals for the wording and paw prints