I'm in the process of re-reading some of Robert E. Howard's mythos stories and find overall that they have a somewhat different feel than Lovecraft's works. Howard's characters seem more active and Lovecraft's more passive in their interactions, and Howard seems to involve more direct conflict rather than simply investigation. I think that this style suits my game group better than traditional CoC and I would like to run some sort of "Howard Mythos" campaign. I don't care so much if it is done with CoC, d20 CoC, ToC, or other rules sets as long as I can capture the mood.
Hey Finarvyn! Long time, no see.
Really (as I think RMP once pointed out), HPL and REH's protagonists/stories tend to run more along a spectrum. Sure, the actual narrator of most HPL tales tends to be somewhat passive. However, what about Legrasse and his men in TCoC? What about Johansen and the crew of the Emma? Those guys did some serious wetwork. Then you have up-close-and-personal combat by HPL protagonists in The Horror in the Museum and Dreams in the Witch-House. You have a frikkin' flame-thrower in The Shunned House.
In the end, the "difference" between HPL and REH was as much about emphasis and POV as anything.
In Howard's work, you see "passive" protagonists from time to time. REH's von Junzt, almost by definition, had to be "passive", to a certain extent, simply to infiltrate and then write about so many cults. If he decided to interrupt a horrid ritual, what would happen then? He had an overriding mission that outweighed such concerns. He had to bring the "bad news" back to an unbelieving Western audience. All else was trumped by that. Very "Lovecraftian".
(3) other than the Howard mythos stories, are there any good resources for that style of play?
There are a few. REH's "weird menace" tales are one step away from the Mythos (due to editorial constraints). His detective yarns tend that way as well (see Price's Drug War of the Black Tong).
That's the thing, Howard's stories all are set in the same universe (and part of the "Mythos universe" at large). A "pulpish" CoC campaign could, very easily, involve elements from REH's weird menace, detective and weird western stories. It could start in New Orleans and end in the "Valley of the Lost." Or, you could even extend things clear to China from there. Robert E Howard has blazed the trail for you.
The thing to remember is, essentially, that Skull-Face is a "weird menace" tale and, yet, HP Lovecraft was all about it. There is no doubt in regard to that. HPL brought up Kathulos in numerous letters to other members of the Circle.
I'll also mention the "Von Junzt" series on Two-Gun Raconteur as a resource:
Keith Taylor and myself spent months collating all of REH's fiction, all of the clues about von Junzt and synthesized that with Lovecraft and the Mythos at large. All of the Easter Eggs therein should keep you busy for a long time, I hope.