Just back from the Transylvanian Alps trek and can easily recommend this trek for anyone looking for a little bit of adventure away from the more frequented mountain destinations.
We were fortunate to have two fantastic guides on our trek, with the primary guide being Răzvan, an extremely experienced guide who demonstrated a fascinating knowledge of the mountains and local history, and we were also joined by his wife Lisa, who was part-way through her training as a trekking guide (with a wealth of experience in all kinds of outdoor pursuits including running, climbing, scuba diving etc) - she will definitely be an excellent guide for future Explore treks! Each evening, the following day's activities were laid out, with expectations set and questions answered.
The trekking was done at what I would consider a fairly relaxed pace, but always enjoyable, and we were lucky to have a good group. The routes varied from gently short hikes (day 1) to longer hikes (day 2) with a bit more ascent (day 3) and ridge walks with some mild scrambling on day 3 (plus an optional one on day 4).
Accomodation varied wildly from comfortable hotels (first and last nights, a lovely little guesthouse in Moieciu (nights 3 & 6), and a pair of mountain huts - one with showers and plumbed toilets (night 2) and another with outside drop toilets, and just a pipe from a local spring supplying the running water. All were fairly comfortable - though while we had gender-specific dorms in the mountain hut on night 2, we (7 fermales, 4 males) were in a single shared dorm those nights.
Food was generally good throughout the trip - a few meals out in local restaurants in Bucharest on the first and last evenings, with locally prepared meals during the rest of the trip. Lunches were mostly a mix of whatever the group carried on each hike, with the guides giving us a bag of fruit, vegetables and snacks to carry, plus a selection of bread, meats, cheeses and tins/spreads which we carried as a shared load amongst the group - do try and leave a bit of room spare in your pack so you can help with this!
The only part I wasn't so keen on was the final day - a few hours in the bus, then an open air museum (in mid-30-40c temps), then spending a lot of time in traffic in the city with a small tour in part of the old town in the same heat. It was fascinating to hear Răzvan's experiences during the Ceaușescu era, but by the time we got back to the hotel (around 3pm), we had not had any lunch, and any plans for lunch had disappeared, so we just went off and did our own thing - it just seemed a bit messy. I think this trip could be shortened down to just the hiking days, and let people just arrange their own city activities/extensions if desired.
The other thing I would mention is the kit list. A lot of the items on that list just were not necessary for this trek - at least certainly not at this time of the year. I ended up leaving my insulated jacket, hat & gloves in my main luggage, and I regretted not taking trail runners or (non-waterproof) hiking shoes instead of boots - it was just too warm for such items, even at altitude. I'd recommend amending the kitlist to note different recommendations based on the time of year.