Need some advice and info

Hello, I'm 20 years old and I'm travelling alone in 13 days. I found some information on the websites but I didn't really understand it so was thinking maybe here someone could help me.

So the first thing would be renting an e-bike.
Initially I was planning on using a public transport but I read on other posts that it is not (busses) really reliable so I was thinking maybe I can rent an e-bike and bring it with myself everywhere except on hikes where I would leave it in the nearby town (if I can lock it onto a specifically designed spot). Also another point would be that I would bring it with myself on the bus (I don't know if locals/drivers find it irritating, also read online that bikes are allowed on busses) but if there is no bus I would ride it myself which would save me from waiting longer/next bus?
Do you think it would be a lot of hassle? Are there any specifically designed spots for leaving bikes in smaller towns or can I chain it to some sign (road sign for example)? Any other advice/idea?

Another thing is that I don't understand how travel card works.
If I'm going to rent an e-bike I don't think I'll buy it for a whole week. But I don't understand do I need to book ticket for ferry if i have a travel card? Does travel card mean that I already have a ticket or I will have to book it anyways?

Thank you in advance!