A very pretty, simple song, just like you wrote, Nateon! I wish you could include the real birdsongs in a final version.
A song describing giving oneself up to imagined or potential love, it left me feeling happier after hearing it. That also may be because I enjoyed watching you and your friend having fun playing/singing together! There isn't anything flashy about the song: the casual strumming of the guitar matched your lyrics about floating leisurely down the Mississippi.
The song ended with what sounds like it should be the chorus: "I'm just a sucker for love." Have you considered using this earlier, too, to create a chorus that repeats a couple times througout the song? Maybe it could replace some of, or come before, the whistled part? Your friend's a good whistler, by the way! Also, you yourself sang this chorus, I noticed...and i didn't hear any reason for you to avoid singing a whole song yourself.
Another thought about the lyrics: I recommend you have all the lyrics relate to being on the river. You sing about walking, and climbing mountains, and you talk about getting tired about chasing her around, but the main recurring image is of the raft (the metaphor the song centers on). If you are going to use the strong metaphor or being on a raft on the Mississippi to represent your pursuit of (and feelings about) a relationship, then I'd prefer you just go all out and describe everything in terms of the river.
As the lyrics stand, first you are on the river raft, then walking, then on the river, then climbing mountains, then on the river with the raft breaking down. All that physical activity of being here and there got kind of exhausting!
Not so much like a raft floating in a relaxing fashion down a river. The song *sounds* like a relaxing, happy raft ride, so I expected more raft in the song.
Final lyrics question: why does the person say he knows he'll always be alone? This doesn't seem to match with the meaning of the rest of the song, which desribes the person overcoming obstacles to get the person he likes to notice him/fall in love. And in the dream of meeting her while rafting, is she supposed to be on her own raft? Or where? You start out with the singer imagining meeting his baby on a raft...then you leave this image unexplained. Is just *he* on the raft? Where is she? (I'm assuming "baby" is a she.) How *does* one meet someone while floating down a river? Is she on the side as he passes by? I imagined her on some paddleboat, and he's on the raft floating behind somewhat, both hopeful and a little hopeless. My point is that if you set up a strong image in a song, I want to see the lyrics following through with that image.
I love the meadow. I wish I could be in a meadow like that!