Part of the fascination of Browning is that you can read many of his poems over and over again and still not really understand what they mean; since he almost never writes in his own voice, you can't always be sure whether the speaker is telling the truth at any particular moment in the poem. Sometimes Browning will throw in something to help us; Bishop Blougram's Apology takes us through the rationalizations and self-justifications of a Catholic priest who doesn't really believe in much of anything except living as comfortably as possible. At the end, Browning makes a rare authorial intrusion to tell us that "Blougram, he believed, say, half he spoke," and that "he said true things, but called them by wrong names" -- that is, Blougram says many things that Browning agrees with, but uses them in justification of an attitude that Browning doesn't agree with. Then we can go back and read Blougram's monologue again in light of what we've found out about him at the end -- but Browning never gives us even this kind of minimal explanation up front. And sometimes, as in "Childe Roland," he doesn't even give us anything to hold onto, any way of knowing what's going on outside the mind of the speaker.
In a way, Browning is the flip side of Longfellow, about whom I wrote a while back. Longfellow's "Excelsior" is a poem about a man who has to continue on a quest in spite of everything; so is Browning's "Childe Roland to the Dark Tower Came." But "Excelsior," apart from not being a particularly good poem, is a public poem, designed to convey a message or a theme to the general reader, with words and sounds chosen for maximum clarity and effectiveness. Browning, who wasn't a particularly well-known poet for most of his career, doesn't care whether we know what message he's trying to convey, or indeed if he's conveying any message at all. And while he was a fine craftsman, he didn't usually seem to care whether a poem sounded good or not; in an era where the most famous poets were noted for mellifluous, beautiful-sounding poetry (Tennyson, Swinburne), Browning let sounds butt up against each other, engaged in some of the strangest trick rhymes in the English language, and created some lines that are positively tongue-twisting when you try to recite them. This is poetry meant to be re-read and puzzled over, rather than recited and loved (even if much of Browning's poetry eventually became loved anyway); for better or for worse, Browning pointed the way toward the twentieth century, where much of the best poetry would require footnotes and special introductions to make any sense. It's often been pointed out that T.S. Eliot's "The Love Song of J. Alfred Prufrock" is heavily influenced by Browning: a monologue by an unreliable narrator, full of obscure allusions and not-particularly-attractive diction.
One Browning monologue I'm currently trying to read through again is Mr. Sludge, "The Medium," one of his last great poems (a lot of the poetry of his later years is incomprehensible in a bad way, not a good way). Browning wanted to attack the kind of seance-holding huckster that his wife, Elizabeth Barrett, had been taken in by late in her life (the modern equivalent would be a Hollywood producer making a movie to attack his wife's conversion to Scientology). It's the essence of Browning that he'd do this by letting the huckster speak for himself and make the best possible case for himself; instead of just an easy hatchet job, the poem places Sludge in the context of a larger problem, that of a society that's lost its way -- Browning, like many Victorian poets, devoted a huge number of poems to the basic question of what a society does when it's entering a post-religious age -- and people who are looking for some semblance of spiritual guidance anywhere they can find it.
One more thing about "Childe Roland": while the story of the poem is hard to understand, the lines themselves and the words Browning uses are actually not that obscure, at least by Browning's own standards. When he let himself go in other poems, he could produce verses full of words and diction that would leave students scratching their heads, that is, if they taught these poems in school, and I'm not saying they should. Two examples. The first, from "Another Way of Love," is a verse that is used in the play The Barretts of Wimpole Street to denote what a strange poet Robert Browning is (when the curtain goes up on one scene, Elizabeth is reading this verse out loud and trying to figure out what it means):
And after, for pastime,
If June be refulgent
With flowers in completeness,
All petals, no prickles,
Delicious as trickles
Of wine poured at mass-time,---
And choose One indulgent
To redness and sweetness:
Or if, with experience of man and of spider,
June use my June-lightning, the strong insect-ridder,
And stop the fresh film-work,---why, June will consider.
Or how about this one, from a very late poem called "Flute-Music, With an Accompaniment":
That's an air of Tulou's
He maltreats persistent,
Till as lief I'd hear some Zulu's
Bone-piped bag, breath-distent,
Madden native dances.
I'm the man's familiar;
What your ear's auxiliar
-- Fancy -- finds suggestive.
Listen! That's legato
Rightly played, his fingers restive
Touch as if staccato.