This was my first visit to Nepal so it was quite a culture shock, and first time every doing a multi-day hike/trek of any kind. I booked this tour as a solo female traveller from, but wasn't worried about going "alone" as I'd have a guide and a porter.
The sightseeing tour was the day after I'd arrived in Kathmandu, we started at 9am but it was already hot and humid. I had the privilege of a private tour (as I was the only one booked) with a female guide. I was given the choice of 3/7 of the nearby UNESCO World Heritage Sites, but I hadn't really done any research about where to visit, so I left it up to my guide. We visited the Boudhanath Stupa, Pashupatinath Temple, Bhaktapur Durbar Square and surroundings. My guide had been conducting these tours for over 20 years, and was very forthcoming with her information, it was also a great contrast to hear about the tours she ran decades ago, before and after the earthquake and now. Our taxi "chaffeur" was never far off, and it was a terrific, easy way to see these parts of Kathmandu without having to try and find my own way through all the chaos.
My guide and porter turned out to be of similar age to me, which worked out wonderfully for us as we got along quite well and playing cards definitely helped us bond. When we met up with other groups at teahouses, as with any other people-service industry your experience will vary dramatically based off your group size, and how well you get on with your particular tour guide.
I feel like I definitely lucked out with Madam (guide) and Saroj (porter) as they were related, and when it came to lunch/dinner time I was usually invited to sit around and hang out with the local Nepali in the "kitchen" area, even though I don't speak Nepali it was pleasant enough to be an observer, I felt very welcomed by their hospitality, kindness, and professionalism.
Despite being quite fit, I chose this particular "longer" itinerary of this trek to force myself to slow down and actually take in all the sights around me. Most of the time we would reach the next camp in about 3.5 hours of walking as I walk quite fast and then basically just sit around until dinner. I'm glad that I chose to do it this way as on the last couple days of the trek where we had to walk for 6+ hours at a time I couldn't imagine having to do that every day of the trek, but then again the last few days are obviously the hardest, and most rewarding. Apart from that the trek itself was a lot of ups and downs, the scenery was so incredibly diverse that at the end of the trip when I was surrounded by nothing but rock, snow and icy mountains, I forgot that I'd cross the river multiple times, walked through jungle, waterfalls, forest, plains, mountainside, stone villages, farming areas etc.
In terms of expenses, everything is pretty much covered once the trek begins. The only time I'd pay for anything was 200MB of WiFi (200NPR) (it was used up so quickly, don't even bother + we enter remote villages quite early on so there's rarely any reception), the occasional hot bucket shower (400NPR), toilet paper x2 (200NPR each, definitely try and find the 3 ply toilet as it will last longer and is more durable).
I was thrilled to hear that the Manaslu Around Trek is actually harder than the Annapurna Base Camp Trek! I feel very accomplished and humbled to have completed this trek. Keep an open mind, don't let little things get to you, just keep walking and you'll have a wonderful time!