I'd suggest you spend some time with fake chord sheet music. I think that will force you to rely upon the chord progressions and strumming for your "song". Country and/or Rock are dirt simple. Here are some Country songs, review some and see what is being done.
http://www.roughstock.com/cowpie/songs/submission Three chords and a four line verse writes a bunch of songs.
http://www.chordie.com/chord.pere/ww...dColdHeart.cpm
If strumming is the real problem. Most every rhythm guitarist I know have about three or four basic strums and then they mix and match those 3 or 4 to the song being played.
Watch ole Hank and his Boom Strum.
http://www.youtube.com/watch?v=4e7UMstGEEk The Boom Strum will play a lot of songs.
Now you mentioned writing songs. Kill two birds with one stone - with an arpeggio finger picking pattern. Provides not only the harmony for your vocal, but does a good job of providing melodic chord tones. i.e melody notes.
http://www.youtube.com/watch?v=P8OmY...eature=related Takes what you are used to doing with a bass line and moves it up to the treble clef -- gets close to a melody line for your song. Then for the actual melody line there is always the pentatonic over the chord changes - draw your
melodic phrases from the pentatonic's notes.
