Technically, this is a cheat/spoiler that involves mods, but posting it here just to be safe due to the spoiler side of it.
There are two TTW mods out there that are pretty awesome - one comes in the optionals folder of Tale of Two Wastelands and is called "TTW Reputations" - it forms factions and gives you the same reputations that you get on the NV side, allowing scales to tip. The other is Chucksteel's TTW Interiors which expands the locations, adds a new quest, and (best of all) gives you both a home in Rivet City but also allows you to own both the Megaton Home and Tenpenny Suite.
When used without TTW Reputations, the process is simple - save Megaton, save Simms, get Megaton House, go do the Ghoul quest for Tenpenny, get Suite.
HOWEVER - this is a bit more difficult for TTW Reputation users, since killing Burke gets you a "Vilified" Tenpenny reputation, potentially blocking off the Ghoul quest because Tenpenny's goons would rather kill you than hire you, even though their only witness to who killed Burke was... well... Burke himself.
So, what TTW Reputation users have to do is 'build reputation credit' first. To do this, don't do the Megaton side first. Save that part for later. Go to Tenpenny and do the Ghoul quest first, killing Roy (and thereby saving the residents of Tenpenny Tower). By the time ghoul bodies hit the floor, you should receive a notice saying that you have been "Accepted" by Tenpenny Tower. You should also get "Vilified" by Roy Phillips, but screw him... he's dead, as is everyone in his faction. Best he can do is shake his tiny fist at you from beyond the grave.
And there we go - reputation credit built up. Let's go spend it.
Go to Megaton and offer to diffuse the bomb w/o pay, but don't do it yet. Go up to the saloon and talk to Burke, getting the device. Now go tattle-tale to Simms about Burke's plan. Follow Simms back up to the saloon and take a position off to the side where you won't shoot bystanders. When Burke starts to rise to his feet, shoot him (easiest way is VATS) before he can shoot Simms. You should receive a notice that you are considered a "Merciful Thug" by Tenpenny (harsher prices w. Tenpenny merchants, but a HELL of a lot better than the "Vilified" that you would have gotten.) Talk to Simms and then go defuse the bomb. Talk to Simms again. Get Megaton House.
Hope this helps folks. If this is the wrong place for this kind of posting or if there's anything wrong with posting this, let me know and I will do what needs to be done to correct it.