When I'm planning out random encounters to spice things up, I'll either choose what I want the encounters to be or roll on the randome encounter table before gameplay starts, then roll each day/night of the in-game cycle to see if that encounter takes place. For example, I like to throw a pysk at the party. He's a prankster and loads sleeping bags with itching powder, sneezing powder, sleeping powder, or steals their shoes. I roll each night they set camp to see if he bugs them that night.
I'll do the same process for a random wildlife encounter. I look for what types of creatures the party would likely encounter and I roll the stats for the creature. I'll roll at random points for travel to see the party stumbles across the creature, if they detect it before it detects them giving them an option to avoid the encounter.
RM gameplay is very different from DnD as we well know. The problem with balancing an encounter to the party levels isn't quite the same in both systems. I've played DnD many times, but I have never DM'd it. I've been GMing RM for decades
I've had relatively weak/innocuous encounters designed to give the party a clue or a bit of intel to help their quest along, only to have the party nearly wipe themselves out from fumbles or really really bad decisions. I've had grand battles planned only to have the Orc captain done in by an E-Slash crit to the thigh on the first dice roll and the goblin party routs. I've had the Pirate Captain stand up from cover to cast his Water Serpent spell, only to have an archer pierce his neck with an arrow. The spell fails, the captain bleeds out, the pirates surrender.
DnD doesn't suffer from Crits so it becomes a war of attrition. Total Hero HP vs. Total Bad-Guy HP. However, tactics can play a deciding part in the encounter. Are the baddies intelligent enough to flank the party? Will a group of four baddies break off to surround and to destroy a single player?
The one thing I've learned from DnD is this: "Get the bodies off the board."
A fresh baddie deals the exact same damage as a baddie with 1 HP remaining. The same holds true for the PCs. A fresh PC is as deadly as a PC knocking on Death's door. Likewise, the party members should be focusing on a single NPC to get flanking and back attack bonuses while a couple of PCs try to delay the larger group. Get the bodies off the board, eliminate or gain flanking and back attack bonuses.
As DM/GM, you can say 6 NPCs are in the group, not 8 NPCs. I don't like fudging the dice either, and I try to avoid it at all costs. However, planning random encounters is better than leaving it to the Fates because we don't like to fudge the dice. I had one random encounter I rolled up and it was a level 9 Wight attacking a party of two brand new-to-RM players, Level 1. I stopped rolling random encounters in-game after that.