We did the length of the Western Isles a couple of years ago at the end of May (on singles - the logistics were formidable even so). I only had trouble with midges once - when the sun came out after rain - when they were pretty bad. Most of the time it was dull and we weren't troubled, so I guess it depends on the weather. 

Restocking with food wasn't as difficult as we'd been led to expect. There's a community shop on Barra (which we didn't use), a good Co-op near Dalabrog (I think) at the southern end of South Uist, a supermarket in Ballevanish near Benbecula Airport, and some small shops in Tarbert on Harris, as well as Stornoway. I think that Sundays are more likely to be a problem as you move North.

Hope this helps. My top tip would be arrange to spend a bit of time on Harris - the most scenic bit. Enjoy!

Edmund 

We visit the Western isles regularly, and in our experience midges are not a problem in early to mid May. Take and use repellent just in case though. Be ready for the classic 'four seasons in one day' weather, which may include unrideable winds.

CalMac seem to be able to cope with cyclists and pedestrians without booking in advance on most crossings, and we would always recommend pre booking accommodation even in well populated places. In the Uists for example it is probably essential.

It is a wonderful part of the world, May is an excellent time to be there.

We went from Barra up to the Butt of Lewis at Easter this year.  Advice is the prevailing wind is from the SW so go this way.  Warning! We had a head wind the entire 7 days.

At Easter it was the very beginning of the season and quite a few things weren't open properly.  There are significant stretches where you won't find tea rooms or pubs.  We took a stove with us so that we could brew up and we really appreciated it.

Barra is great, South / North Uist are pretty flat and boring - the wind can really get you there.  Comments on Leverburgh are spot on.  The Harris Brewery Bar is great for beer and food.  We stopped at a little B&B Taylor Hill, which was superb.  The previous night we had stopped at Temple View Hotel on North Uist which was great.  Really friendly owners (only just taken over) who had a great border collie. 

North from there the scenery gets much more dramatic and the beaches are fantastic.

One to watch - Doune Braes Hotel in Lewis.  It's fine but reminiscent of Fawlty Towers.  Don't be in a rush for anything.

One of the hardest days we had was from the Butt of Lewis to Stornaway.  There isn't much on the way and its not flat and very open, so the wind can get you.

We organised the whole lot through Hebridean Hopscotch who sorted ferries and accomodation.  This way the whole lot was co-ordinated between ferries and accomodation and was down to them.  Also its then insured.  Beware inter-island ferry times can change on the day, so have a contingency plan.  

Mobile coverage was surprisingly good.  There is Wi-Fi at all the ferry terminals.

The only bit they couldn't do was the transfer of the tandem. We did this with Alistair Glover at Bespoked Bicycle repairs in Stornaway.  He took us all the way south from Stornaway to Castle Bay.  He is pretty much the only bike shop and support on the entire route.  He is really helpful and will come out to people who need him, but I'd recommend going self sufficient with tools and spares.

We went from Oban, leaving the car there.  We decided to go back down the Hebrides rather than trying to return from Ullapool on the mainland.  This worked well, and you get an opportunity to see the islands another way.

It is a superb trip!

Hi John. We have spent a number of years in Scotland cycling and walking and the midges don't seem to follow a pattern that I can work out. I think they are very much weather dependent. They don't seem to come out when raining or in strong winds but you probably don't want either if you are cycling. So the best advice is be prepared! Keep covered! Long sleeves, Long Trousers and a hat with a midge net (they don't look great but they work!). Also a good repellent helps. We use Smidge but there are many others, so it's worth asking in a local pharmacy. Also apparently they can't catch you when cycling provided you keep above 5mph! So don't stop or cycle too slowly. Enjoy your trip and the scenery makes up for the midges! Martin