any suggestions on the best time of year to be away from a smallholding???)
If you have only sheep, then just before tupping. If you buy a tup in, get back before he comes. The lambs are away or speaned and settled; the ewes are in good condition prior to tupping, not working, don't need anything except reasonable grass; the hay is made and in; the fly season may be past, else use Clik or Crovect. Worm everything before you go

Next best is after tupping. Depending on where you live, risk of getting stranded by weather, however.
If you have other species too, it's harder! When we wanted to attend a wedding at the end of June, and have a week's holiday afterwards, our planning started in the preceding September. We didn't AI anything for a month so there would be no chance of any cows calving while we were away. (It happened to be the year we had no bull. If we'd had a bull, we'd have run him with the Blue Greys for that month. They should have been in calf anyway, but if any had returned, they almost never have any calving or rearing issues.). Tups had to be out by the end of December so that all lambs would be at least 4 weeks old when we went away, and I had to be mindful with the pet lambs that they had to be speaned and settled by mid-June; any late ones would have to be sold once they were well established. And everything was dependant on being able to organise haymaking, shearing and so on, for other times - so right up until two weeks before the wedding, it wasn't certain that ex-BH would be going too. We were phenomenally lucky to have a divorcing farmer staying with us when the time came, or to be honest I think we'd have been too worried (about flystrike, mastitis, and all the other things that can hit sheep and cattle in summer) to have enjoyed the holiday.
(I hope all the folks who buy their new smallholding and 'want some of everything right away' read this thread!)