If you've time I've made a couple of small Alterations to your route with a run up Glenaan and down Glendun and instead of going along the Seacoast road at Benone going up to the Bishops Road past Manannan Mac Lir, a Celtic sea god at Gortmore viewpoint. Also the option of visiting Binevenagh viewpoint. From Gortmore on a clear day you get stunning views of Donegal, the Ayrshire coast and Islay and Jura. If its wet I'd stick to your original route and if its windy I'd give Malin Head a miss. Of the Donegal headlands Fanad is much more senic IMHO of course. If you are looking for grub on the way up. Harbour Lights in Carnlough, McBrides in Cushendun and for ice cream Morelli's in Portstewart are all good shouts.
For day 2 I'd take a run up to Fanad head then go down via the Harry Blaney bridge to Glenveagh. Worth stopping at the old Ruined Church at Dunlewey and if you have the time talking a wee detour to the Assaranca waterfall at Ardara.
As an Alternative for day 4 turning off before Kylmore Abbey and talking the road past Lough Inagh R344 is a lovely run and much less traffic than the N59 then turn off the N59 again and do the Roundstone loop and Approach Clifden from the South. About that area the Alcock and Brown crash/landing site(Marconi Radio Station) is worth a stroll round time permitting.
As an Alternative for day 4 turning off before Kylmore Abbey and talking the road past Lough Inagh R344 is a lovely run and much less traffic than the N59 then turn off the N59 again and do the Roundstone loop and Approach Clifden from the South. About that area the Alcock and Brown crash/landing site(Marconi Radio Station) is worth a stroll round time permitting.
An alternate suggestion depending on time: Ballina - Crossmolina- Kennagh cross roads - wild nephin park - lough Feeagh - Furnace village - salmon weir - Derradda - mulranny- corraun- achill. You miss the very north coast but it is a great run if you are getting loads of sea in Galway! I love the road from Cliften to Maam Cross as well - fast AF and good scenery but if the mrs is on the back your original Galway route is a good bet….enjoy! Also forgot to mention Sheeffry pass on the way into Leenaun is worth a look.
If you do stick to the North Mayo coast, take in the head land Pullathomas - Inver - Barnatra then take the road on the west side of Carrowmore lake (you may already have it) and on to Ballycroy then Achill. When leaving Achill, don’t miss the route via Corraun into Mullranny.