Only use jack stands or hydraulic jacks that have an ANSI/ASME label on them and have an appropriate wt. rating. Use a suitable plank under them. Do NOT use jacks or jack stands under the frame only for support.
Cribbing is the safest method for support if lifting the frame off the ground. From a structural point of view, to get max. stability you'd make the width of the cribbing twice the height of it. A lesser width at the base may work but ensure it's on stable ground - may need some planks to spread the load out. I would not do it like in the photo on a travel trailer as this could shift due to the tall height vs width of base. Don't support the frame at the 4 corners -support it fore and aft of the axles and put down the stab and tongue jacks. Make sure the trailer can't move side to side at the front or rear.
Another method is ramps like in the illustration below. Use X-chocks or equiv. and put down the jacks. This would be the fastest (and probably safer) method but the trailer will be at an angle (if parked on level ground) but could probably use ramps under the rear of the TV's tires.
Post a few pics of the work in progress. :)
