Heya! I went to NCS alone and really enjoyed it
I went on the three week program so for me it was as follows:
Phase One -
This is adventure week, personally my group went to Kingswood in Doncaster. We did three activities per day iirc like Jacobs Ladder, Rock Climbing, Zipwire, Archery, Rowing, Rafting, Abseiling, Scavenger Hunts, Team Bonding activities etc. Honestly, the first week is super super fun and you won't really be bored. There's also things like camp fire nights and just more chilled game nights with your group where you may play cards.
Phase Two -
This is the residential week. Personally, my group went to the University of Essex. We stayed in their dorms and we got a taster of university life. I can't remember loads about this week but you get quite a lot of freedom, there's sessions like sex ed, metal health, sea life pollution and stuff that we needed to attended but there's activities to make it fun. Like we put condoms on dildos, made vision boards and did a craft project for the sea life stuff. You also get a hint of the party life and we got to use their night club one night.
Phase Three -
This is the community week. This will be local to your home and you will carry out a project in your community. This often includes fundraising then carrying out your project. My group did a bake sale and raised like £100 then we did up an old peoples home garden by making it more sensory etc.
If you go on the 4 week program your phase three will be two weeks instead of one week, but honestly the third week was my least fave and it's when you are just in your group theres no more meeting people outside of that group so I think the three week program is enough!
I really do recommend it, I made 6 really good friends there and we all still travel and meet up from time to time. It definitely is an experience I feel you will benefit more from if you go alone, quite a lot of people do and its a time to meet people rather than feeling like you owe something to your former peers.