1 day at Kusatsu with sleep over

Initally I planned my trip to kusatsu with 2 days hotel, if I was to change this from 2 days to 1 day would there be enough time.

Whiles stay in kusatsu my plan was to visit Mount Shirane, various bath house which includes Sainokawara Rotemburo, Otakinoyu and Shirohatanoyu bath house.
And to buy some souvenir.

I should be arriving at kusatsu about 1310 or earlier if i get the earlier train and make my way direct to Mt.Shirane, the Yugama crater from Naganoharakusatsuguchi Station if there is a direct bus, if not I will have to make my way to kusatsu bus terminal. I will be spending about 4 hrs or less at Mt shirane, then back to kusatsu near the yubatake to visit Sainokawara Rotemburo, on the way to the hotel i will shop around for souvenir and check in to the hotel (Hotel New Shichisei) then to Otakinoyu, if I have time i will goto Shirohatanoyu bath house.

would this be alright.

If you do not mind a relatively fast pace of travel, one night can be enough, although it depends on what time you have to leave Kusatsu on day 2.

Access to Mount Shirane and back is time-consuming. If you plan on arriving in Kusatsu relatively late (around 1pm), I would not expect to have too much time left for Sainokawara Rotemburo and exploring the town afterwards, considering that you should check into your hotel no later than 17:30. If possible, I would recommend to try to be in Kusatsu earlier than 1pm.

I can take the earlier train and should arrive at kusatsu around 1110, I have contacted the hotel that I will have a late check-in, but I can also check-in after returning from Mt. shrine, so it shouldn't be a problem.
I will be looking around, but mainly after some Yunohana minerals powder, lot of friends requested these from me.

As for leaving, i'm travelling solo, so my time is very flexible, but i should be leaving kusatsu 0700 and arrive back in the tokyo area about1030 and make my way to shinagawa.

I have the intention to visit enoshima instead of shinagawa, is this correct the kanto area pass only covers the train route to kamakura, and not direct to enoshima.

I will be looking around, but mainly after some Yunohana minerals powder, lot of friends requested these from me.

They are widely available at the numerous souvenir shops.

As for leaving, i'm travelling solo, so my time is very flexible, but i should be leaving kusatsu 0700 and arrive back in the tokyo area about1030 and make my way to shinagawa.

In the morning? Evening? If you mean morning, you will not have enough time to see all the sights on your list even if you arrive earlier on day 1.

I have the intention to visit enoshima instead of shinagawa, is this correct the kanto area pass only covers the train route to kamakura, and not direct to enoshima.

The closest JR station to Enoshima is Fujisawa, a 150 yen train trip away from the island by Odakyu Railways:
http://www.japan-guide.com/e/e3117.html#jump_access

How much time is normally needed to see mt shirine , the yugama crater including the bus journey to and from mt shirine.

I would allocate about an hour to see the crater. The bus timetable will be a deciding factor on how much time it takes in total.

With further searching it should take about 30 minutes to and from mt shirane, and with about an hour up at mt shirane, i'll give it about 3-3.5 hrs.

If time is the problem I can give up on Shirohatanoyu and/or Gozanoyu, but lake Yugama, Sainokawara Rotemburo and Otakinoyu is a must.

But look at the opening hours Shirohatanoyu closes the latest at 2300 so I should be able to fit this in.

But i'll see what happens once i'll get their.

thank