I think "Gibbon" is a typo or mis-transcription for "Gibson" meaning Ft Gibson.
On the 16th, I think Phillips is saying he has ordered, but it has not happened yet: "I sent a force up the Canadian to the Seminole country to sweep north to the Arkansas, crossing and marching to Gibbon [Gibson] on the north side; Maj. Foreman with another up Little River to pursue the same course [Foreman describes this route in his Jan 1865 report]. I shall send another up North Fork [now known as the North Canadian River] and return with my baggage and forage train direct to Gibson." Phillips gets back to Ft Gibson on Feb 24th.
On the 14th, Phillips says "I had sent the infantry and wagons with Col. Wattles back from Middle Boggy to Little River" -- sounds like the infantry made the march in one day(?). On the 16th, he says Wattles reached "this point" with the infantry and the train on the 14th and that he will "...return with my baggage and forage train direct to Gibson."
On the 16th, Phillips says he is 105 miles from Ft Gibson. What is the mileage from the mouth of Little River to Ft Gibson? Perhaps a better way to ask the question is what is 105 miles from Ft Gibson via the Dragoon Trail? Foreman reports (Jan 1865) his marching distance from where he crossed the Arkansas to Ft Gibson as 80 miles. He came to this north-south road 100 miles south of the Arkansas. Is it 100 miles from Keystone Dam to the mouth of the Little River?
You are correct on the location of the 'original' Ft Arbuckle, constructed by Lt Dawson in the 1830s (on the north side of the Arkansas near present Keystone Dam)... and as the story goes, they tried to send a boat up the river and had to offload the cargo and hurry down river to keep from getting stranded. The Dawson Road crossed the Arkansas just west of where the dam is now and the ridge visible to the south of where Hwy 412 crosses the lake is Dawson's Ridge. I think Foreman is talking about the Dawson Road in his Jan 1865 report mentioned above. This is the road Gano and Watie used after 2nd Cabin Creek to bring the captured train south AND is the road Cooper used in 1861 at the Battle of Round Mountain (far east of Yale and the Twin Mounds in Payne County).