If the batteries are of the same type, i.e. both are NiMH or both are Lithium-ion, then you can use a higher capacity (i.e. higher mAh) battery instead of the lower one. The reverse is also true.
People visiting Table Rock are not allowed beyond the Mill Creek Watershed boundary, which is clearly marked with numerous signs. As mentioned earlier, the Mill Creek Watershed is a closed watershed and no public access is allowed, as it is the municipal water source for the city of Walla Walla, Washington.
The shortest route to the top and to this view is via the 3.7 mile Table Rock Trail. However, when I do this hike, I generally start out going up Pinnacle Mountain Trail to the west, make a stop at Mill Creek waterfall, and cut over on Mill Creek Pass Trail to Panther Gap, and then on to Table Rock's summit.