So glad you have a buyer; and that you have found somewhere you like.
We moved a year ago (OH then 70; me 68) to a bungalow - a bit bigger than yours sounds, as there are 3 good bedrooms.
We have benefited hugely from the fact that it is all on one level, as neither of us have great mobility.
The downside is that the move seriously took it out of my OH who has PD. I did all the legal, estate agents, financial stuff, but he found it very hard to stand back from doing too much as regards moving stuff about, trying to put up curtain rails etc. - he now has bilateral inguinal hernias!!
So my advice to you is: take every tiny bit of help you can get - get the removers to pack for you. Do not underestimate how stressful it all is; and how much less able to cope with that you are in your 70s.
Spare stuff was much appreciated by recipients on Freecycle.
Lots of good luck in your new life - enjoy! 