In September 2019 Andrea and I paid a return visit to the Royal Botanic Garden, Edinburgh. My first tip would be to park and ride from the outskirts of the city, the trains are fast and frequent. Then get yourself a day ticket on the buses. The 27, 15 and 16 still go from Princess Street to Inverleith Row for the Botanic Gardens.
Admission to the gardens was free, but there is a charge for the greenhouses. Watch carefully in the next few years as a lot of work is being carried out in the gardens and certain glasshouses like the old Palm House will be closed for some time. There is a small eating area by the East Gate entrance, however it is worth walking over to the West Gate complex for the various eating areas and extensive shop.
The garden has changed a lot since my days as student 1973-6, I might be biased, but the plant collections are not so extensive and not maintained as well as I believe they were in my student days and the3 peat gardens and walls were almost an embarrassment. It was nice to see the Pinus I had grafted in 1975 was still on the rock garden, albeit a little large for its site now. Over impressions were good and would recommend a visit to anyone interested in plants.