Upgrading an 855 Fork from a rigid?

[BigO]

Hello Fellas!  So ive been doing tons upon tons of research on Proflex and components as I am trying to do a few upgrades to this dinosaur. Sadly somewhere upon the line, my 855 was stripped of its original Vector fork and replaced with a sad, sad rigid fork. I am currently trying to find a decent suspension fork, new or used, to replace it. What kind of things should I be looking at when considering a fork? I understand we have a 1 1/8th straight steerer tube, which correct me if I'm wrong can fit a tapered 1.5 to 1 1/8th fork with the addition of a Cane Creek XX44 style headset adapter. Granted I will only take this route if I cannot find a straight steerer fork. My other concerns are given our older geometry style, I don't want to put too much stress on the frame by having too much travel in my fork. I read somewhere else that I should limit my travel to roughly 100mm? Would 120-140mm be too much? The latter seems to be more common nowadays. If its relevant, I am 6'4" and about 200lbs and plan on doing mostly XC style riding with light jumps around the SoCal desert area. Thanks guys!

[singletrackmac]

I highly recommend the rockshox recon silver tk. It's a great value, easy to maintain and can be adjusted to run from 80mm, 100mm or 120mm. It is plenty stiff for xc riding which is what this bike is designed for. I am 6'4 240lbs and this fork works great for riding on the more xc oriented singletrack up in Lake Tahoe. Which, being Lake Tahoe, is pretty aggressive for xc riding. 

https://www.sram.com/rockshox/products/recon-silver-tk-0

http://www.chainreactioncycles.com/us/en/rockshox-recon-silver-tk-solo-air-forks-9mmqr-2016/rp-prod136309

If you want to check out some other 100mm 1 1/8th steerer forks I would look here:
http://www.chainreactioncycles.com/us/en/forks?f=2258,4294957577,4294964891,4294957536,4294945319
This is just their 100mm 1 1/8 forks. I would not go with any more travel than that, and if you go with the recon, I would set it to 80mm. The bike will handle much better at 80mm than with 100mm. You will gain better performance by trying to preserve the original geometry than you would from an additional 20mm of travel. Also, I would not mess with the head set adapter thing to go from 1 1/8 to 1.5 tapered.  Best thing to do is keep things simple with this bike and not to spend too much money,

As for longer travel forks, that is not what this bike is designed for. It is better to keep the center of gravity low and preserve its quick handling, nimble and fast accelerating geometry, which helped it win Dual Suspension Bike of the Year in Mountain Biking mag's 1995's Dual Suspension Shootout. This bike will turn circles around the the long wheel base, slacked out, long travel wagon wheeled bikes they make today. This 855 is best on tight, fast and twisty singletracks. Putting a long travel fork will only slow this bike down.

But, it's your bike so here is 41 fork options that will fit the 1 1/8" head-tube on the 855.
http://www.chainreactioncycles.com/us/en/forks?f=2258,4294964891,4294957536,4294945319
If you want to maybe transfer this fork to a modern bike some day, you can use a 27.5" fork because there is only a 1/2" difference between 27.5" and 26" in wheel radius. If you get a new tapered head tube frame, you can get head sets that will fit the straight 1 1/8th steerer to a tapered head tube.