The Cele Route is definitely worth the detour. I agree Day 2 was the most beautiful. You are hiking up on La Cause (limestone cliff like plateau) along narrow paths with steep drops to the side. Stunning.
Peche Merle is worth the visit but I personally found it slightly amusing that they tried to call certain markings in the caves the drawing of a woman or a mammoth etc. Grasping at straws slightly if you ask me! Other cave markings / drawings were of course alot more impressive. Myself and the pilgrims I was hiking with dud have a good giggle about it afterwards though. By the way Peche Merle is not recommended if you are very claustrophobic or if you have certain medical issues with the reduced O2 levels etc down there. It does feel slightly uncomfortable in that respect so bear it in mind.
I found accommodation generally very good on this side route but like others it is definitely a good idea to book ahead and definitely at least 2 to 3 days in advance during busier times.
Its worth noting that mobile phone signals are not always good there so you may not be able to phone ahead or make calls when you think you can (from memory I think Espagnac Sainte Eulalie had this issue).
From memory, it may have also been Espagnac Sainte Eulalie that didn't have any shops for food either (I'll edit this later if incorrect). We arrived on a day when the only restaurant in the village was closed and the hostel was booked out. They ended up opening up the restaurant specially for all the pilgrims for the evening meal and breakfast the next day. Plan ahead if you don't want to be caught out food wise.... The gite d'etape communal was not my most favourite place on this route. Well the village is very pretty but unfortunately the hostel was not the best run/organised. Maybe they were having a bad day. At any rate they messed up our booking. We had to wait around for hours before the person running the place turned up (very late) and got everyone sorted. Luckily the weather was good as we had to wait outdoors with nowhere to buy food or get a coffee. I was just relieved to get a bed as it was looking dodgy for a while.
This route is definitely more strenuous than the Le Puy route and the sections on the road tire the legs more so this is worth bearing in mind when planning stages. We ended up taking shortcuts on the road to shorten one or two of the days that were particularly long.
This is where we stayed in May 2014. All as listed in Miam Miam Dodo 2014:
BEDUER: Chambre d'hôte Gite d'etape Nadia et Jean-Pierre Masson. Beautiful new gite. 5 in one room. All single beds. Spotless. Personally I found Mr Masson a little gruff to start. One tough customer!
His wife is lovely though and we had a beautiful evening meal with them that evening. A little tricky to find. Tel 05 65 38 12 60)
ESPAGNAC: Communal gite. Tel 05 65 11 42 66). Mixed standard of rooms. Didn't come across as being particularly well run but it was fine. Limited food options in this village (no shops and only one restaurant so enquire when booking and come prepared!). No phone signal in village. Book other accommodation in later villages advance of arriving here...
By the way the stretch between Espagnac to Marcilhac was the highlight of the entire Le Puy route for me. Stunning hiking up on La Cause.
MARCILHAC SUR CELE: Gite d'etape Accueil Saint Pierre (new and not listed in MMD) tel 05 81240630. Double, triple or 4 person rooms available. Tip: Rooms on top floor have single beds if you prefer them to bunks. Lovely place. Friendly owners. Options to cook yourself if I remember correctly or DP €34. We took DP option.
CABRERETS: Gite du Barry. Tel 05 65 22 91 79. Nice owner. Gite a bit neglected but fine. Her restaurant La Roue next door to gite is great for food and a cold beer. We ate at restaurant O'Louise as the people I was walking with were on a tighter budget than me. The food or wine was not the best quality so recommend you eat/drink at La Roue instead. Its from here you walk to Peche Merle which is on the GR 651. Book ahead so you get the earliest English tour available. Steep climb out of village to the caves so allow extra time than you think you'll need for the distance to get there on time.
BOUZIES: Gite Mr Guiral. Tel 05 65 31 28 43). I shared a tiny twin room but kitchen was great for cooking communal meal and owner had some food,beer and wine available for sale if we needed it. Nice owner. Stove in kitchen dining room lovely. €19 b&b.
PASTURAT: Le Relais du Pasturat. Tel: 05 65 31 44 94. Lovely rooms in upper floor of 'barn'. Clean and simply furnished. Nice area to sit outside in garden. Can buy beers off owner etc and they provided a lovely evening meal. DP €33. We booked 3 beds in room for 4 people.
Ok that's my list. The MMD has a good list of places to stay. Its not a full list but it will help you on your way.