My dealing on HMA last year was if it is accessible BLM or state ground included the rules did not count. This was striaght from the wardens mouth. Not sure on walk in..
That's not entirely true...there are exclusions to what you just said. Pinto Creek HMA (Mariah Ranch owned by the OSLI) is one that I can speak of specifically that you need permission to access for hunting even though a county road touches State land.
I would be cautious of making blanket statements in regard to when and where you need permission in regard to HMA's...
IMO/E, its best to ask specifically about the HMA or WIA you're wanting to access.
The HMA/WIA programs are too good to see squandered by misinformation, if in doubt ASK first. Even better, just get your crap together and get the permission slips you need and it makes all this discussion irrelevant.
That's one of my biggest pet peeve's, no matter how much you try to make these programs rock solid, some toolbag is always looking for a loophole or think they're special. I'm all about being able to access public lands, you wont meet anyone who is more passionate about that, but in this case, just get the permission slips. If you're not willing to do that, then verify with the access coordinator about the specific public land in question.
Don't take anyone's word for it, or wrongly assume that just because a county road touches the public, in particular State, that you have default legal access...you may not.