Norcalplanner

The Karbonite mod by RoverDude has a version of what you're looking for in the form of Karborundum fusion torch drives. They use water and fuel at a 50:1 ratio (same as a NSWR) and have an Isp of 25,000. They're going to push some stations and other craft featuring SSPXr and other NF parts to Grannus for me.

My rule of thumb is 2/3 of the way through the atmosphere if you're still under power. Then again, I tend to play in upscaled systems and try to do single burns to orbit, so I frequently don't have much of a coast phase. As others have said, hang on to the fairing if you've already cut your engine and are coasting to Ap.

Beacons are starting to be deployed, and the Gael - Thalia route is open. Gael - Gratian should be open soon. Here's one of the medium ones fueling up with Karborundum before heading out. Learned the hard way that the medium stations are only good for up to 60 tons or so. Karborundum costs go up rapidly over that mass. Also sent a Longbow to Grannus on a high speed transfer with plenty of Karborundum. Should be there in about 15 years. Edit: And now the Gael - Gratian route is open. Time to spend more time working on atmospheric craft and surface bases... :-)

I'm a big fan of the RD-181 myself, simply because it's a bit more versatile. Compare it to the Skipper, and the RD-181 is superior pretty much across the board. RD-180s are good too, but they're a bit too powerful to be used as a second stage in my typical applications.

Launched a new Karborundum miner to Thalia in my 2.5x GPP career, since the drills on the previous iteration were glitching and refusing to do anything. Also launched the whimsically named Parkehnrhyde Station, intended to be a transfer station for those who will be using the under-development ESLD jump beacon network. Not the most aerodynamic thing on ascent... ...but it looked pretty good once in orbit and the centrifuges were inflated with 9000 material kits. The final on-orbit station has only 29 parts, so hopefully lag won't be too bad. A big shout-out to @Nertea for SSPXr and the awesome station parts contained therein.

Patience, good sir. I'm still lashed to the mast of Karborundum on my current career save, but I'm already planning the mod mix for my first 1.4.x career, and The Spice is front and center. I'll also be ditching MKS and focusing on WBI's suite.

RSS with SMURFF works well, though, because the mass of the capsule is reduced so much. +1 on suggestions to make small corrections far away from Earth. I'll also add two other suggestions - first, dump or burn any excess monoprop that you don't need to maintain orientation during reentry prior to entering the atmosphere to reduce the craft's mass. Second, burn every bit of remaining fuel in your service module or transfer stage prior to reentry to slow down. I've had good success with creating a node between 1000 and 3000 km altitude so that you can dial in the precise amount of radial out needed to maintain your desired Pe. I recall that the heating flux is a function of the cube of the velocity, so scrubbing off just a few hundred m/s is still a worthwhile exercise.

I harbor illogical warm feelings towards that thread where we all learned about gate orbits. Good times... [sniff]

It's possible to launch into orbit in stock for only 3200 m/s with a halfway decent rocket and ascent profile, and 3100 m/s with an optimized design. Doing the math based on these lower numbers should get you in the ballpark.

The main station on the left is powered by an Osprey engine from Near Future Launch Vehicles. Both it and the Thalia Express (bottom portion of the photo) can get away with only with only 3 medium extending radiators each, as they stay in high Thalia orbit (currently 1,000 km). The Karborundum miner, on the right side of the photo, is a different story. It has six large curved radiators around its 2.5m reactor, plus eight medium extending radiators and four large extending radiators. You also need to be aware of the heating bug - pausing the game while mining, or going beyond 1000x time warp can mean destruction for the unwary. The surface of Thalia is not for the faint of heart.

Someone (OhioBob?) said that the base version without any of the extras is working in 1.4.2, but the full version with all the bells and whistles is still being worked on. If you're playing a rescaled game, or enjoy the new content provided via Kerbal Konstructs, then we're still in a waiting pattern. Some aspects are dependent on other mods which aren't quite up to snuff yet for 1.4.2. Honestly, given the number of bugs which were introduced in 1.4.2, I'm still playing my 1.3.1 GPP 2.5x career and waiting for 1.4.3.

Continued exploration in my 2.5x GPP career, in what is rapidly turning into the Karborundum Space Program. We landed a probe on Geminus, getting a good view of Gratian. That was followed by launching and fueling up a mid-size ESLD jump beacon. It'll wait for the next transfer window to Gratian. A large ESLD jump beacon, fully fueled with Karborundum, departed for Grannus at high speed. Lastly, the Karborundum-powered Thalia Express crew transport arrived at Thalia... ... and eventually docked with the combined orbital station / Karborundum miner. Now Galileo, Jade, Sigma, and Bobert have a way to get home.

Newer versions of GPP (with Kerbal Konstructs installed) have multiple launch sites, and upgrades the KSC with additional launch pads and a heavy runway.

I'm working up a mod list for a new 1.4.2 career, and am hoping to get some better performance this time. With that in mind, is there any thread or guide regarding which mods cause the biggest performance hit? Alternately, are there game play techniques which can be used to reduce lag and increase FPS? Currently playing a highly modded 2.5x GPP career install, and starting to get tired of frame rates in the teens. FWIW, computer is an i5-6600k with a mild OC, 16 gigs of ram, a SSD, and a GTX 960. Also FWIW, Scatterer is already on the list of mods getting axed, and I'm strongly leaning towards giving up my beloved MJ.

All my beacons are fully kitted out, fwiw.