Here are the general time allotments we used when we did PHFHG...
Once we had done school for a month, this is the longest it took us to do PHFHG:
Left side of plans...
Reading about History: 15 minutes
(T)
Research/Geog./Timeline: 20 minutes
(S)
Independent History Box: 20-25 minutes
(I)
History Project box: 20 minutes
(S)
Storytime: 20 minutes
(T)
1 hour 40 minutes
Right side of plans...
Math: 20-30 minutes
(S)
DITHOR: 30 minutes (3 x a week)
(S); Creative Writing: 20-30 minutes (1 x a week)
(S)
Dictation: 5 minutes (3 x a week)
(S)
Grammar: 15 minutes
(S)
Bible Study: 15 minutes
(T)
Science: 20- 30 minutes
(I)
Poetry: 5 minutes
(T)
2 hours 10 minutes
As far as teaching time, the "T" boxes indicate teacher-directed times. The "S" boxes indicate semi-independent times, and we found that this varied between our 2 dc that we did PHFHG. My oldest is a go-getter, a get-it-done kind of guy. My middle ds is a smell the roses kind of guy. So, my time with my middle ds when we did PHFHG with him last year took longer than it took with my older ds many years back.

The "I" boxes are independent, though of course there is still teacher time in correcting the work and making sure it is done properly (though not much time

). I took time to bold each of the boxes above with letters indicating whether they were teacher-directed, semi-independent, or independent. Each of our sons were round 8-9 yo when they respectively did PHFHG. I would assume a fourth grader could work more independently. I'd say my teaching time with PHFHG, to ballpark the total, was around 2 hours each day. PHFHG was pure joy to teach both times for me! It is an awesome guide, and I can't wait to do it again in a few years with son #3. HTH!
In Christ,
Julie