Plan for search engine optimization and accessibility

Your company has joined an industry accessibility group and you are a member. As one of your responsibilities, you have been asked to estimate the time it would take to modify your corporate site for accessibility. What should you consider to properly estimate the required time? (Choose all that apply)

The amount of text in the website
The numbers of controllers in the application
The complexity of your data entry forms
The level of current usage of HTML helpers in your views