Russian Language Use in Pimsleur - Dope or whack?

Factual Questions
1

I am studying Pimsleur Russian and, not knowing for sure, I see criticisms of its usage. For example, Pimlseur says

Я должен/должна был/была остаться дома. - (mas./fem.) I was supposed to stay at home.

Guys on the internet claim that this:

Я собирался/собиралась остаться дома. - (mas./fem.) I was supposed to stay at home.

is the correct method.

Another example:

PIMSLEUR:
Мне нужно было пойти пешком сегодня утром. - I needed to go on foot this morning.

INTERNET GUYS:
Мне нужно было идти пешком сегодня утром. - I needed to go on foot this morning.

or possible:
Мне пришлось пойти пешком сегодня утром. - I needed to go on foot this morning.
Can someone who knows more address how accurate the Pimsleur syntax is? Are the internet guys maybe not understanding that maybe Pimsleur is teaching a more formal phrasing that is still correct? Or Will I sound like a doofus in Санкт-Петербург if I use Pimsleur’s phrasing?

2

Pimsleur’s syntax matches what I learned in high school and college (and recently on DuoLingo) for the first sentence. My understanding of Я собирался/собиралась остаться дома is less “I was obligated to stay home [and got in trouble for leaving]” and more “i was planning to stay home [but the house caught fire so I didn’t]”

The second set deals with the difference in perfective and imperfective and verbs of motion for a double-whammy Russian idiosyncrasy. The Pimsleur sentence is more focused on the start of the action, whereas the internet guys are a little more focused on action itself. I might use the first one if I had to go on foot because my car was broken down, but the second if the fact that I was walking was important. I’d trust a native here, probably.