For a good weather window you need to keep an eye on the mountain weather and Scottish ski conditions websites. With a reasonable forecast it is great up there.
I was up there in April last year and the conditions on the White Lady on Cairngorm was how I remember it from fifteen years ago; 50mph winds and little visibility. Fortunately my skiing has improved since then. Access to the White Lady was only by the mid station funicular so at least you had a rest between runs.
Finishing at Glenfinnan the year before I did a bothy tour in April and the main issue that time was the amount of water in stream crossings, wet feet paddling is highly likely.
I have a dog tag with name,blood group and passport number on it. ICE on phone to her indoors.I reuse waterproof envelope labels and put them in a lot of the stuff in my pack,wallet,phone etc.
My insurance details are in Dropbox on the phone. in case I am not able I have a note in my wallet and passport for Physicians to contact my Insurance company to gain permission before treatment- seems extreme I know but I met a guy on a US trail stuck with a $3000 bill for ER treatment and layover after a snake bite.