We are trying to decide between CTI or CSS and wonder if anyone can offer advice/opinions?

I have a bad knee (OA) which while it doesn't limit what I do (except very deep steps/stairs) it does cause me pain if I do lots of stairs/slopes.

We are keen to use the AN facilities at whichever hotel we book - is the boat to TI easy to access or is it a very big step up/down? Would hate to get there and not be able to use the island!

I know CSS is built more on the hillside and therefore there are more steps but will most things (pool, beach, restaurants and room) be on the same level?

Thanks for your thoughts