Never trust a map
I will describe this hike in three segments: 1) Pine Creek Trail #289, 2) exploring the southern end of Big Bug Mesa, and 3) descending Pine Creek from the line shack to Seaton Spring.
Pine Creek Trail #289: The trail is a decent surface the first two miles, but crosses Pine Creek many times, and is slightly up & down though, obviously, tending up. At 0.4 miles, on your left, will be junk pile. At 1.1 miles, on your left, will be a corrugated metal tank, with two probably dry tanks made of metal, lined on the inside with stone & concrete. At 2.6 miles, will be the unusual triple box metal tank. All three boxes were full of decent water when I saw them, and one was trickling over, so they were obviously receiving fresh water. The trail is now on the west side of the creek, and beginning it's climb to the rim. In less than a hundred yards, on the east side of the creek, if you look closely, you will see a small metal box: Just on the other side the box is Seaton Spring. The box was full of decent water when I saw it. Now beware, despite what FS Topo and MyTopo would have you believe, I could find absolutely no evidence that the trail continues north up Pine Creek. Instead, it turns left / west, and gets steep, and slippery with pebble gravel. At 3.0 miles you will hit the rim, not far from the small stone wall. Though I did not see any dirt bikes, keep an eye out for them as they have left tracks on Trail #289.
Explore: There are numerous jeep trails on the southern end of Big Bug Mesa. Lots of fire rings too. I followed a jeep trail for awhile, then cut cross country towards Hill 7020. Cross country travel varies from stony (both granite and what appears to be volcanic), to dead fall riddled, to smooth grass. No matter which, it's pretty smooth sailing. Just before Hill 7020, there is a trail heading left / west, and down. I did not follow it the whole way, but it appears to head down towards Old Dandrea Ranch. Hill 7020 has great views of Moscow Peak, Mount Union, Mount Davis and Turkey Creek. You can even see the San Francisco peaks in the far distance! I saw no other hiking trails in the area, but instead followed another jeep trail east, to the rim overlooking Wolf Creek. More great views. The line shack used to just be a shack, but the house ruins -- surrounded by an amazing amount of junk spread overal several acres -- used to actually be a nice house. Not sure what happened, but shame it ended up that way. Too collapsed to look inside. There are lots of fences and gate-less gates in the area.
Descending Pine Creek: From the line shack, you have two choices: 1) either work your way west, then southwest, along the rim for a mile back to the top of Trail #289 at the stone wall, then diddy bop on down, or 2) drop into Pine Creek and scramble the next half mile to Seaton Spring. As I said earlier, there is no evidence of any trail between the line shack and Seaton Spring. Side-sloping also was not practical the couple of times I tried it. Despite the creek bottom being choked with rocks, and much deadfall, and even a few more barbwire fences, the creek bottom is actually your best route if you drop into the canyon. It's only about 0.3 miles to Seaton Spring, but your track will be twice that distance due to dodging & weaving. Cross Pine Creek at Seaton Spring, hop back on Trail #289, then book back to the trailhead.
Note: There are two tracks on my uploaded route: The first track for the actual path Trail #289 follows -- as opposed to the misdirection claimed by FS Topo and MyTopo -- and the second track for exploring the mesa, then returning via Pine Creek.
Gate Policy: If a gate is closed upon arrival, leave it closed after you go through. If it is open, leave it open. Leaving a closed gate open may put cattle in danger. Closing an open gate may cut them off from water. Please be respectful, leave gates as found.
This hike is listed as One-Way.
When hiking several trails on a single "hike", log it with a generic name that describes the hike. Then link the trails traveled, check out the example.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.