Tenglong cave

1) Yangtze River cruise usually includes peapod boat if the water condition allows. Tenglong Cave is not included.
2) From Yichang or Chongqing, you can take a high speed train to Lichuan first; duration is about 2.5 hours and 1.5 hours respectively. Upon arrival, take the specail bus line to Tenglong Cave directly. The bus departs right from railway station; ticket fare is CNY5.

thank you so much. my cruise doesn't include peapod boat.
Do you know the cruise has option to join while cruising?

2) Do I need to make bus reservation ahead for lichuan to tenglong cave?
Yichang to lichuan or yichang to enshi...which is better to take a bus to tenglong?

Yes, the cruise has options but you need to pay additionally for them.
I'm a little confused about your second question. Anyway, Lichuan is the best transfer place to reach Tenglong cave and there is no need to reserve the bus in advance.