Please suggest a 7 day Hawaii

We are going to spend 7 days in Hawaii. Please give some precious suggestion on the schedule and hotel infor.:

1. My hu*****and will be in a conference for the first 3 days and the reminding 4 days we will be together.

1. We will return from Big island. Do you think it is a good idea to book hotel on big island and travel to other islands such as maui and oahu?

2. Can you recommend some hotels which are on budget and nice ?

3. Any suggestions for attractions?

thanks a lot