All souls will eventually get into Heaven; some just take longer to get there in the "cosmic, settling of accounts" sense. The bad, definitely have to spend some time in purgatory to work off (or something?; purging, like a sick patient who has to suffer before she feels better?) bad karma, or in Judeo-Christian parlance, "sin." I'm not exactly sure what it means when Franklin below speaks of souls not going right to Heaven, but rather, "some place where souls are prepared for those regions."
But he clearly believed in such a place. To see his entire words in context, it's from his letter to "Mrs. Partridge. On the Death of Ben Kent.—Orthodoxy. (extract.) Philadelphia, Nov. 25, 1788."
"You tell me our poor friend Ben Kent is gone, I hope to the regions of the blessed; or at least to some place where souls are prepared for those regions! I found my hope on this, that though not so orthodox as you and I, he was an honest man, and had his virtues. If he had any hypocrisy, it was of that inverted kind, with which a man is not so bad as he seems to be. And with regard to future bliss, I cannot help imagining that multitudes of the zealously orthodox of different sects, who at the last day may flock together, in hopes of seeing each other damned, will be disappointed, and obliged to rest content with their own salvation. Yours, &c. B. Franklin."Apparently being "honest" and "virtuous" counts for hope of salvation, according to Franklin.