A VOR APRCH WAS ATTEMPTED AT THE ORIG DEST BUT A MISSED APRCH WAS MADE AT MINIMUMS. PLT DIVERTED TO JAX WHERE HE WAS CLEARED FOR AN ILS RWY 7 APRCH. THE ACFT WAS NOT EQUIPPED WITH GLIDESLOPE OR MARKER BCN, BUT ATC PERSONNEL STATED PLT MADE IT APPEAR THAT HE WAS EQUIPPED FOR FULL ILS APRCH. XING ALT AT OM IS 1900 FT; FLT CROSSED OM AT 400-500 FT. AT ABOUT 4.5 MI FROM RWY, FLT CLIMBED TO 900 FT, THEN AT 3.5 MI, DESCENDED TO 600 FT. ATC ADVISED FLT OF RADAR-OBSERVED ALT EXCURSIONS DURING THE APRCH. THE PLT STATED THAT HE GOT ON THE LOCALIZER, TRACKED IT FOR AWHILE, THEN GOT OFF. HE WAS TRYING TO RECAPTURE THE LOCALIZER WHEN HE HIT THE TREES ABOUT 1 MI SHORT OF THE RWY. THE PLT'S BFR HAD EXPIRED 2 MOS PRIOR TO THE CRASH & REVIEW OF HIS LOGBOOK SHOWED NO EVIDENCE OF COMPLIANCE WITH FAR 61.57, RECENT IFR EXPERIENCE. THERE WAS NO EVIDENCE OF ANY PROBLEM WITH THE ACFT OR COMPONENTS.