Tokyo - Kamakura - Kawasaki

Hi
I would like to visit the Great Budha in Kamakura area, Nihon Minkaen Open Air Museum and Kanayama Shrine from Tokyo in one day. The last two are at Kawasaki.
I will start from the Great Budha and I know how to get there from ShinjukuJR station (at this point my JR Pass will have been expired).
Please advise how to get
From Kamakura to Nihon Minkaen (Kawasaki)
From Nihon Minkaen to Kanayama Shrine (Kawasaki)
If I start around 8am what time roughly will I be back to Tokyo ( consider us as slow traveller )

Thank you

Have you tried checking Google Maps and/or Hyperdia?

From Kamakura to Nihon Minkaen (Kawasaki)

This page explains access to the Minkaen:
https://www.japan-guide.com/e/e3253.html

As you can see, the closest stations are Mukogaoka Yuen and Noborito. So, the easiest route would be taking JR from Kamakura to Noborito with a transfer at Kawasaki.

From Nihon Minkaen to Kanayama Shrine (Kawasaki)

The closest station to the shrine is Kawasaki Daishi Station. So, the easiest route would be taking JR Nambu Line from Noborito to Kawasaki and transfer to the Keikyu Daishi Line to get to Kawasaki Daishi.

If I start around 8am what time roughly will I be back to Tokyo ( consider us as slow traveller )

I would expect slow travelers to be back in Tokyo around 6pm, but it is difficult to guess your pace.

Thank you all, really appreciated

As mentioned, Minkaen is not "at" Kawasaki Station at all. It's "in" the City of Kawasaki, but out in the suburbs far away from the station named Kawasaki.

I love Nihon Minkaen, and it is a vast park that is bigger than a small village. As you can see, you also need to take a bus that is not very frequent, or walk for a very long time from a train station. Additionally, it is open only during the day, and the last bus is before the park's closing time.

I strongly recommend you to take a whole (sunny) day just for the Minkaen. That way, you can take a shorter route instead of traveling via Kawasaki Station.

Kamakura equally is full of attractions. Take a whole day or at least half a day just for Kamakura.

I hope you have fun!

@Uco thank you for your input. I realised that Nihon Minkaen might need a lot more time than I originally plan to spend , and I finally have to admit that transportation is a little bit too much for us, so I came to a decision to spend the day at Kamakura instead. Anyway thank you for your advise

If Minkaen is too much for you yet still intend to go to Kamakura, perhaps you'll be interested in parks like the following.

Shinbayashi Park:
This is a cozy park that only neighbors know, and it is quite accessible from Kamakura. The Koike family's house built in 1841 is preserved here and open to the public 9 am to 4:30 pm except on Mondays. From Kamakura, take the Enoden train to Ishigami station and walk about 10 minutes.
http://www.city.fujisawa.kanagawa.jp/kouen/kyoiku/leisure/koen/fujisaw...

The Enoden itself is a cute little train that runs through the old part of the ancient capitol, offering a great view of the ocean as well. You should ride it even if you're not visiting the park.

Sankeien Garden:
This is a popular yet not-so-crowded garden in Yokohama City. The Yanohara family's house built around 1750 is preserved here and open to the public. There are also some other old buildings (not homes) here, and the garden is much easier to walk around in than the Minkaen. Take a bus from Negishi station.
http://www.sankeien.or.jp/kokenchiku/yanoharake.html

Since there is not much else around the park and garden, you may want to visit either of them first and then go to Kamakura where you can finally enjoy dinner after seeing the Budda among other attractions there.

Hope it helps.