Let’s examine two cases:
You want to use prebuilt one page Bootstrap template with yii2. How hard it is to swap from what you get with yii2 application templates to actually being able to create one page app ?
You do not event want to use Bootstrap, you want just some nice HTML5/CSS3 template. How hard it is for you to change ?
I have tried both and my conclusions are:
in case of 1): impossible without using extra technologies like Angular.
in case of 2): not impossible, but you will have more than few things to do.
Do you have any guides or tips ? What are your experiences ? I am starting to lose interest in using framework