So I have been doing some online researching and it appears at Buckner Mountain (or Mount Buckner) has mainly had summits from the west, or north face. However, I was wondering if it had been done, or even if its possible (without ice axes) to summit Buckner from the east side, via park creek pass.

This also would be in March '15.

Thank you!

March-early April is our peak snowpack in the Cascades so I hope you expect that this will be a snow-climb. I've never personally been up Buckner but I have summited Eldorado around that time of year. Skis or snowshoes might be necessary for the approach and parts of the ridge. I would advise against forgoing an ice axe because you will encounter steep snow-slopes at some point near the end where trekking poles alone would be dangerous. Cornices will be building and you may also encounter 5th class sections, a bergschrund and possible gendarmes on the way.

I won't say it's impossible but for me it would be an unreasonable risk in March.

I found some links to parties who ascended via the SE ridge, yds 5.8, on Cascade Climbers, none of which took place before June nor did they come from Park Creek Pass:

http://cascadeclimbers.com/forum/ubbthreads.php?ubb=showflat&Number=1127978

I don't have a clear understanding of your climbing history but I hope you understand that this is a serious and technical undertaking. At the very least it will be adventurous. I recommend finding some partners also interested in your route.

I am trying to comprehend how you would even approach Buckner that time of year.

Good point! I forgot that the North Cascades Highway (SR-20) is closed every year because of snow. It's gated from milepost 134 to 171.
http://www.wsdot.wa.gov/traffic/passes/northcascades

Without a snowmobile it would be an epic adventure just to get to Buck Creek Pass (you would only go there from SR-20 otherwise you'd approach from Stehekin). Sorry to burst your bubble but your adventure does not seem reasonable.

It would be possible to approach via Cascade River Road, but that is typically impassable from MP 13 or so, which would mean a 10 mile hike/ski/snowmobile ride to the end of the road. From there one could hike up Sahale Arm and then drop into Horseshoe Basin and climb onto Park Ridge, but I don't think that is what the OP meant. Really serious avalanche terrain up there.