Study the Fender schematics of the 60's.
The circuit is not too complex, but does require some space for two tubes and a transformer, as well as the associated parts on the board.
Basically.... what they do is steal a little signal from the preamp. The signal goes through a fairly small coupling capacitor, to keep the lows out of the reverb signal. The size of that capacitor is CRITICAL for good reverb tone, but... you can experiment with it after its all built and working. The signal goes through both sides of a 12AT7, chosen for its current handling capacity. The stand alone units use a 6V6 (the reissues do at least... originals used a... something similar, but a bit smaller, I forget the type). The 12AT7 (or 6V6) are set up as drivers for the reverb tank itself. The driver is a single ended audio amp, class A, and drives the tank through an output transformer that impedance matches the tube to ... 8ohms, just like a speaker. Thats right, Fender tanks are 8 ohms on the input side. The tank has a transducer that vibrates the springs, and a receiver that senses the vibrations. This is essentially a mini speaker connected via spring to a mic element (worked out in detail so it functions properly of course). The "mic output" of the tank is high impedance, so it goes through half a 12AX7 for amplification back to preamp levels, then is mixed back into the signal chain. After mixing, which eats some signal strength, its amplified one more time by the 2nd half of that 12AX7, and after that, the two channels of the amp are mixed and enter the driver.
Pretty much just copy and past the Fender circuit into your own, tweaking only needs to be done to the input coupling cap to the reverb circuit - typically .001uf or even 500pf, but you may find 250pf or even 125pf useful. The TYPE of capacitor is also fairly critical, and I find that ceramic caps do the best, even though the "silver-mica" are better. They're too good, and you get a harsh reverb with them (I've found). The output at the mixing stage also needs to be tweaked, typically they use a large resistor and a very small bypass capacitor where the two signals are mixed. The resistor is something like 3.3 to 10 MEGohms, while the bypass cap is in the order of 10pf to 47pf according to brightness tastes. If you get the resistor too small, you get a LOT of gain in that channel, but the reverb quality suffers a whole lot. Similarly, you can get some really ace reverb but the channel itself will suffer if you go too large on the resistor - and dont take the time to finely match the capacitor that is used to bleed the highs around the big resistor.
Simple no?