Detailed Camera Paths can only be a maximum of 30 minutes long.
You can create consecutive paths that overlap. Save your path, then remove all but the last two pairs of keyframes. Manually edit the keyframes (double click, not drag) so that the first pair now has a timeline position of 0:00 and the second pair are similarly moved up BUT remain the same relative time after the first as they were originally. This will involve calculation (by subtraction) using their original timeline and timecode values. Timeline values are Minutes:Seconds:Milliseconds but timecode values are JUST in milliseconds. Once you have the two pairs of keyframes at the beginning of the timeline you can continue creating the camera path.
When rendered the two clips should overlap and can be edited together. The reason for keeping the first two pairs of keyframes is so that the spline curve extrapolation of the camera path remains smooth.
